crustacean parasites of west indianfishes and

CRUSTACEAN PARASITES OF WEST INDIAN FISHES AND LAND CRABS, WITH DESCRIPTIONS OF NEW GENERA AND SPECIES.

By Charles Branch

Wilson,

Departmentof Biology, StateNormalSchool, Westfield,Massachusetts.

INTRODUCTORY.

During the

summer

of 1910 the author enjoyed the privilege of spendingthree

months

atthebiologicallaboratoryofJohnsHopkins Universityat

Montego

Bay,Jamaica.

As

a partofthe

work

thereaccompUshed about100species offish,'

including

many

hundreds ofspecimens,wereexamined forparasitic copepods, isopods, and other parasites that might be of peculiar interest.

Many

ofthelarger Crustacea,

and

inparticularthe landcrabs,were alsoexamined forthe

same

purpose, andseveralpeculiar

and

unex- pectedparasiteswerefound

upon

theirgills.

And

finally differentkindsofascidians, ofwhich

many

species live

upon

the

mangrove

rootsaroundthe

Bogue

Islands aboutamileto thewest of the town, and

upon

the oceanbottom in that vicinity, were carefully examined in order to obtain the various copepods, isopods, and amphipods, which are commensals or semiparasites withinthem.

The

presentpapergives the results of these examinationsandis chiefly concerned with the copepods although one

new

species of ostracodisdescribed. Forthe opportunityofprosecutingthisstudy andfortheexcellentlaboratoryprivilegeswhich werefurnishedsin- cere thanks are returned to the authorities of the Johns Hopkins University.

To

Dr. E. A.Andrews, the director of the laboratory, theauthorisindebtedforvaluable suggestions

and

advice.

And

to the authorities of the United States National

Museum

a deep obligation for

much

timely assistancein thisand

many

othersimilar investigationsisacknowledged.

Proceedings_U.S.National Museum,Vol.44—No.1950.

190 PROCEEDINGS OF THE NATIONAL MUSEUM.

vol. 44.

FISH

AND

FISHERIES.

The

regionaround Montego

Bay

isthe centerofthemostextensive fisheriesinJamaica.

Every

partof theharborandtheshorefor 10 or 15 milesto theeast and westofthe

town

contributes

some

fish to the market.

The

methods employed in catcliing these fish are rather crude, boththe boatsandtheapparatus used being primitiveandnotvery wellconstructed.

The

boatsare practicallyallsmall dugouts

made

from nativetrees, and thefishingtackle consists ofpots and traps, haul seines, gillnets, cast nets, and

hand

lines.

By

farthe largest

nymber

offisharctakeninthepots,whichconsist ofa

wooden

frame-

work

covered withsplit cane, bamboo, or in recent yearswith wire netting.

These potsarescattered allover thebottom, where itissmooth, both inside and outside of the coral reefs, in water from 1 to 12 fathoms deep, and are pulled every morning before ttie sea breeze roughens the surface.

The

haul seines are also used extensively along thenumerous sandybeaches.

The

actual

number

offoodfishesobtained, aswell as the

number

of species,isquitelarge,and

by

requesting the fishermentosavesuch kinds as are usually thrown

away

or used for bait, the

number

of speciescanreadilybedoubled. There were broughtin forexamina- tionduring the past seasonabout 100 recorded species,nearlyallof which were caughtinfishpots.

A

verylittleeffortwith theseine andlinefishermenwould easily increasethisnumber. Againthesupplyofallthe

common

speciesis constant for long periods of time, the

same

kinds being obtained daily, thus insuringan abundance of fresh materialfor

work

either with thefishthemselvesorwiththeirparasites.

Ofthe selachians the sharksareratherscarce,only afew

hammer-

heads (Sphyrnazygsena)and oneortwospecies of Carcharhinus being caughtduring thesummer, but theyare said to be

more

plentiful at otherseasons.

To

offset this scarcity ofsharks thereisan abundance ofsting (Dasyatidse) andeagle (Myliobatidse) rays,theformeroften ofverylargesize.

Among

the

bony

fish thegrunts (Hsemuhdse), the sea basses and groupers (Serranidse), and the parrotfishes (Scaridse) are especially numerous.

The

mullets(Mugilidae),the

pompanos

(Carangidse),the snappers(Lutianidse),the croakers (Scisenida),andthebutterflyand angel fishes (Chsetodontidse) are also abundant.

The

pipefishes, (Sygnatliidae), the trunk-fishes (Ostraciidse)^, the puffers (Tetrao- dontidse), and the porcupine fishes (Diodontidse) can be obtained almost everywhereandinlargenumbers.

NO. 1950.

CRUSTACEAN PARASITES OF FISH AND CRABS—

WILSON. 191 Beside these forms,which

may

bedesignatedasthe regularcatch, oddspeciesare continuallybeing takenbothin thefishpots andin theseines, andifthe fishermen be inducedto save theseandbring

them

in forexaminationitwillbefoundthattheyincludeduring the season agoodrepresentationofnearlyevery family that occursinthe

West

Indies. Inthis

way may

oftenbeobtained theremora (Eche- neis naucrates), the sea-bat (Ogcoceplialus vespertilio), the spotted

moray

{Lycodontis moringa), thecutlassfish(TricMuruslepturus),the galliwasp (Sy nodusfoetans), andthe flyinggurnard (CephalacantJius volitans), togetherwitha hostofother

odd

^forms.

Many

of the marine fish run far

up

into the fresh-water rivers, especially the muUets and pipefishes,but there are about a dozen strictlyfresh-waterspecies, includingtwo or three darters,mudfish, catfish,and thelike. Thesearenot oftencaught

by

the nativesbut

may

easily be obtained with a seine. All the rivers are swift and turbulent streams exceptforthe shortdeadwaterneartheirmouths, andduring the rainy season they

become

powerfultorrents,sweeping

down

into the sea everything thatgetscaught intheir current.

At

such timesnofish can be obtainedfromtherivers, and even under favorable conditions the supply is limited.

To

escape being swept

away many

of thefish haveacquired the habit ofburrowing under the rocksorgoinginto holes inthe banks,wliichaddstothedifficulty ofsecuringthem.

On

lowlandtothewest ofthe town, betweenthe

Montego

Kiver and the ocean, is a portionof the old bed of the river, which

now

forms a good-sized

pond

filled with brackish water andplentifully suppliedwithfish

and

Crustacea.

This combination of salt, fresh, and brackish water furnishes exceptionalfacilities for thestudy offish and their parasites.

And

itwould be^difficulttofind aregion bettersuited forsuchinvestiga- tionthan

Montego Bay

andtheimmediatevicinity.

PARASITIC ISOPODS.

As

might be^expected,parasites ofallkindswerefairly

common m

Jamaica.

But

while there

was

awide diversity ofform andnearly everyanimal

was more

orlessinfestedwiththem, theactual

numbers

were remarkably smaU.

More

parasiteshaverepeatedlybeentaken from asinglefish at

Woods

Hole, Massachusetts, or onthe coastof Maine,thancouldbeobtainedfrom a scOreof

them

hereinJamaica, and to a certam extent the

same was

true of the Crustacea and ascidiansthatwere examined; there

was

the

same

dearthofnumbers.

The

parasiticisopodswere aboutthe only exceptionto thisgeneral rule. In the temperate regions of both the Atlantic and Pacific oceans theseparasitesarequiterare, buthereinthetropicsthey are

192

PROCEEDINGS OF THE NATIONAL MUSEUM.

vol.44.

abundant and surpass in

numbers

^all the other parasites together.

They swarm

ⁱⁿ the eye sockets and the

mouth

and gill cavities of

many

of the

common

fish, and are especially abundant

upon

the parrot fish, thegrunts, and the snappers. Other species are found living as commensals witliin the bodies of ascidians, sponges, and thelike.

A

large

number

of specimens were obtained from these various hostsand weresenttotheUnitedStates National

Museum

for identi- ficationandstudy.

^

PARASITIC COPEPODS.

As

hasjustbeenstated with referenceto theisopods,itwas found that a careful examination of any large fish would usually yield copepodparasites.

But

while there

was

anabundanceoftheisopods there would be only one or two, or at most a very few, copepods.

And

evenlargecatchesoffishwere alwaysdisappointinginthe

num-

berofcopepods obtainedfrom them.

The

resulthasbeen acollec- tion ofcopepodparasites, very meagerin the

number

ofspechuens, butcomparativelyrich inthe

number

of species.

In the following ^list an effort has been

made

to include all the copepodspreviously reportedfrom

West

Indianfishalongwith those foundduring the presentinvestigations.

Nearly all of these published species are included

m

two papers, bothofwhich are confined, so far as the

West

Indiesareconcerned, to theDanishislands inthegroupofLesserAntilles.

The

firstpaper^{^}

was

written

by

Steenstrup andLiitkenand pub- lished in1861, andthe second

by

Kr0yer,^ publishedin1863.

Many

of thespecies which they reportedwereobtainedfrompre- served specimens ^ofDanish

West

IndianfishintheVienna

Museum

while others were brought

home

by the captains of various vessels which

had

cruised inthat portionoftheAtlantic.

So faras can be ascertamednota single specieshas hithertobeen describedfromliving material.

The

present report is the exact antithesis of this, for every

new

specieshere presented hasbeendescribed,andthedrawingshave been made, from living specimens before preservation, and in addition

some

oftheDanishspecies, publishedinthetwopapers above men- tioned, wereobtainedalivefrom Jamaicanfish, and

upon them

were verified the original specific descriptions. In all thereare herein- cluded 52species, ofwhich21 have been previouslydescribed,while 31 are

new

to science.

>See Richardson,Proc.U.S.Nat.Mus.,vol. 42,No.1894,April5,1912,pp.^187-192.

«Kong.DanskeVid.Selsk.Skrivt.,5tc.Raekke,p. 343.

sNaturh.Tidsskr., 3die.Raekke,p. 75.

NO. 1950.

CRUSTACEAN PARASITES OF FISH AND CRABS—

WILSON. 193

FamUy ARGULID^.

The

apparent absence of thisfamilyfrom thefaunaofJamaicais

worthj^ of comment. Species of Argulus have been obtained from

Key

West, Florida; from

New

Orleans, Louisiana; from Dallas, Texas, and from

many

localities in Central and South America.

Theseincludebothsalt and fresh water formsand

show

thatinthe surrounding faunas,which mostresemble thatofJamaica, the family ArgulidtBisfau'ly wellrepresented.

Hence we

should naturally look forasimilarrepresentationintheJamaicanfauna,anditseems

more

reasonabletosupposethatthefailuretodiscoverany

member

of this familyonthefishofJamaicahasbeen theresult ofaccident rather thandue to then- entireabsence fromtheregion. Careful searchin the future

may

bring to light

some

Argulus species, but asimilar search during the seasonof1910

was

unsuccessful.

FamUy ERGASILID^.

ERGASILUS LONGIPALPUS,newspecies.

Plate18,figs.1-6.

Hostandrecord ofspecimens.

— A

singlelot,consisting of sixfemales,

was

taken fromthegillsof several puffers {Chilomycterus antennatus) at

Montego

Bay, June 6, 1910.

Type-specimen.—Csii. No. 43512, U.S.N.M. Paratypes, Cat. No.

42258,U.S.N.M. ^•

Female.

—

Cephalothoraxovate, one-fourth longerthan wide,with evenly curved lateral, and a slightly reentrant posterior, margin;

neither dorsal grooves nor eye visible.

The

first three free thorax segments the

same

length, but diminishing regularly in width, the

fij'stone (secondsegment) three-sevenths thewidthofthecarapace;

fifthsegmentindistinguishably fusedwiththegenitalsegment,which

isthe

same

width

and

about twice thelengthof the fourthsegment.

Abdomen

two-thirds thewidthof thegenital segment and

made up

ofthreejoints ofequal length; anal laminae smalland^circular,each tipped vnih. twosetae, the innerof whichis twice the length ofthe outer. Egg-tubesnarrowed posteriorly,two-thirds the

body

length;

eggs small, in sixor eightlongitudinalrows,about20 eggsinarow.

Firstantennaeof theusual pattern; secondpairwith moderately enlarged basal joints

and

astout terminal claw, bent sharply near thecenter

and armed

there with a rounded protuberance on the inner margin.

Mandibles with a ^lender neck, a narrow terminal blade,

armed

withsetgealong the inner borderonly,andalargesecondarytuft of setaeattheinnerdistalcornerof theneck.

Mandibularpalps exceptionallylongandnarrow, reachingbeyond thetipof the basaljointalmost tothe centerof the terminalblade.

69077°—Proc.N.M.vol.44—13 13

194 PROCEEDINGS OF THE NATIONAL MUSEUM.

^vol.44.

In this they are peculiar, since in other'specics the tip of the palp doesnotproject

beyond

theendofthe basaljoint. Firstmaxilla a largeknob,

armed

withtwo equalsetae; secondmaxillawith alarge and stout basal joint and a short terminal blade, which does not reach the midline; terminaltuft ofsetaeshortanddense.

Rami

of

swimming

legs three-jointed, except the exopod of the fourth pair, which has but two joints; arrangement of spines and

setaeas follows^: Firstexopod,I

—

0,

—

1,

—

6; endopod,

—

^1,0

—

2,

1—4.

Secondexopod,

I—

0,

I—

1,

0—6;

endopod,

0—1, 0—2, 1—5.

Third exopod,

0—0, 0—1, 0—6;

endopod,

0—1, 0—1, 0—5.

Fourth exopod,

I—

0,

0—5;

endopod,

0—0, 0—2, 0—4.

Fifth legs wholly lacking.

Color auniform cartilagegray,withoutpigment markings ofany

sort, quicklybecoming light

brown

inpreservatives.

Totallength, 1.20

mm.

Cephalothorax, 0.75

mm.

long, 0.6

mm.

wide. Genital segment, 0.1

mm.

long and the

same

width.

Egg

strings, 0.76

mm.

long, 0.20

mm.

wide.

(longus, long,andpalpus, apalp,alludingtotheexceptional length ofthemandibularpalps.)

Thisspeciesisdifficult to distinguishexcept

by

the

mouth

parts, wherethe projection of the long and narrowpalps beyond the tips of the basalmandibular joints, andtheshort terminaljoints ofthe secondmaxillae areverynoticeable. ^*

ERGASILUS MYCTAROTHES,newspecies.

Plate18,figs.7-12.

Hostandrecordof specimens.

—

^{Sevenfemalesof thisspecies,four}of whichcarried eggstrings, were taken from the

mucus

in the nasal tubes of a

hammer-head

shark, Sphyrna zygsena.

Type-specimen.

—

^{Cat. No. 43597, U.S.N.M.} Paratypes, Cat. No.

42255,U.S.N.M.

Female.

—

^General

body

formelongate

and

narrow; carapaceellip- tical,nearly twiceaslongaswide,narrowed aboutequallyanteriorly andposteriorly,with shallow,butdistinct,notchesinthelateralmar- gins two-fifths ofthelengthfromthe posterior end,whichindicatethe point of union of the head with the first thorax segment. Free thorax and

abdomen

only two-fifths as long as the carapace and tapering rapidlyposteriorly; second, third,,and^fourthsegmentsthe

same

length, but diminishing regularly in width; fifth segment so completely fusedwiththegenitalsegmentthat thereisnoindication oftheunioneither inagrooveorina pairofrudimentaryfifth legs.

Genitalsegmentbarrel-shaped,alittlewider thanlong,withconvex lateralmargins

and

apair of short,broadlyroundedposterior lobes.

Abdomen

three-jointed, jointsdiminishing regularlyinlengthand width; terminal joint with a deep anal incision; anal laminae con-

NO. 1950.

CRUSTACEAN PARASITES OF

FISH

AND CRABS—

WILSON.

195

siderably longer than the basal

abdomen

joint

and

half as wide as the terminal joint, enlarged at the tip and

armed

with two large setae,the innerofwhichisfourtimes the lengthoftheouter. Egg- cases cylindrical, aslongastheentire

body

and twice thediameter ofthegenitalsegment; eggs rathersmall, in fiveorsixlongitudinal rows,from20to25ineachrow.

Firstantennseshort,only reaching the centerofthe basaljoint of thesecondpair,

and

sparsely

armed

withsetae.

Secondantennae stoutandtwo-thirds the lengthofthecephalotho- rax; basaljointmoderatelyenlarged,theremainderoftheappendage taperingregularly,witha small

knob

ontheinnermarginofthe penul- timatejoint close to thebase of the terminal claw; thelatter with twosmall teethonitsinnermargin nearthecenter.

Labrum

only indistmctlyvisible; mandibles large

and

stout, the terminalbladebroad

and armed

withsetaearounditsentiremargin;

palpsvery narrow andneedle-like,aslongastheterminal blade

and

witha

row

of fineteeth alongtheiroutermargin; firstmaxillae small, notprojectingmuch, and

armed

withtwosmallplumosesetae; second maxillaeratherlarge,but withsmallterminaljoints,whichoverlap at the midlineandareheavily

armed

withsetae; novisibletraces ofthe maxillipeds.

The

firstthreepairs of

swimming

legs withthree-jointed rami, the exopodof the fourth pairwithtwo jointsonly; thearrangementof the spinesandsetaeas follows: Firstexopod,I

—

0,1

—

0,

—

_{^6; endo-}

pod,

0—1, 0—2, 0—5.

Second exopod,I

—

0,

I—

1,

0—6;

endopod,

I—

1,

0—2, 0—6.

Third exopod,

I—

0,

I—

1,

0—5;

endopod,

I—

1,

0—2, 0—6.

Fourth exopod,

I—

0,

0—5;

endopod,

I—

1,

1—2, 0—5.

Colorauniformcartilagegray without pigmentormarkingsof

any

sort.

Total length, 0.95

mm.

Cephalothorax, 0.7

mm.

long, 0.4

mm.

wide. Egg-strings,0.9

mm.

long,0.18

mm.

^wide.

(fiuKTTjpodsv, outofthenose.)

This

new

species

may

bedistinguishedfromothers

by

the elongate eUiptical shape of the cephalothorax, by the extreme shortness of the

body

behind the cephalothorax (see above measurements),

by

the greatlength and uniform diameterof theegg-cases, and

by

the thickness of the

"neck"

of the mandible, the width of its cutting blade,andthelinearformofits palp.

BOMOLOCHUSNOTHRUS,newspecies.

Plates 19and20.

Host andrecordof specimens.

—

^Fifteenspecimens, including both sexes, were obtained from the gill cavity of the httle fish locally

known

as*'sheepshead," Abudefdufsaxatilis,onSeptember5.

196 PROCEEDINGS OF THE NATIONAL MUSEUM.

^voi,.44.

A

^singlefemale

^was

^{found on thegillsof a tobaccofish,Aleutera}

sa-ipta, but as this fish

had

been tumbled into the boat

mth

^the

sheepsheads thecopepod})robably gotontoitin

some way

fromthe latter. Thissinglespecimen is

numbered

42257, U.S.N.M.

Type-specimen.

— A

female,Cat.No.43590,U.S.N.M. Paratypes, Cat.No.42253,U.S.N.M.

Female.

—

^General

^body

^{form rather short and stout; carapace}

twice as wide as long, squarely truncated posteriorly and with a shallow notch at the center of the frontal margin. Second, third, andfourthsegments subequalin length, butdiminishing regularlyin width. Second segmentone-thirdnarrower thanthe carapace,leav- ing the firetlegs visible on either side; a partof the basaljoints as well as therami oftheother

swimming

legs visibledorsally. Fifth segment the

same

length as the fourth and only a little narrower;

genitalsegmentthe

same

widthasthefifthsegmentandrathershort, with convex sides.

Abdomen

two-jointed, the basaljoint widerbut shorterthan the terminal; anal laminae small and rectangular, each tipped with a long innerseta, ashorterouterone, and twospines,oneat the outer distal corner, theotheratthecenteroftheouter border.

Egg-strings four-sevenths of theentirelength, the

same

width as thegenitalsegment, andslightlynarrowedattheposteriorend;eggs in five or sixlongitudinal rows,from 15 to 16 eggsineachrow.

Firstantennae prominent;basal portion considerably widenedand strongly arched, carryingtwolongtactilesetaB towarditsdistalend.

Secondpair largeandstout,theterminaljointtippedwith twolarge finger-like processes, one dorsal and considerablysmaller, the other ventral, and between

them

two long, curved claws and a straight spine.

A row

^ofbluntlyrounded

comb

teethruns along theanterior marginofeachfingerprocessand ontothejointitself;the

row

from the dorsal processstops atabout thecenter of thejointwhile that fromthe ventral processruns thewholelengthoftheanteriormargin of the joint and curves around its proximal end to the posterior margin.

Upper

lip triangular, nearly twiiee as wide as long, with straight sides

and

well rounded corners. Mandibles bent sharply backward andendingin astraight

and

slenderspine.

FirstmaxiDse witha longcurved paragnath andaprominent

knob armed

withthreeplumosesetae,ofwhichthetwo

mner

onesare close together,curvedinward towardthemidlineand thenbackward, and arefour times the lengthof theouterone, whichisremoved alittle distancefrom

them

andpointsdirectlybackward.

Secondmaxillaecurved forward andinward, notquitemeeting at themidline, their terminal blades

armed

with a

row

ofshort hairs along theanteriormargin. Maxillipeds^vitha large triangularbasal

NO.1950.

CRUSTACEAX PARASITES OF FISH AXD CRABS—

WILSOX. 197 joint and a rather slender, strongly curved terminal claw, with a long accessory spine attheposteriorcurveoftheS.

First

summing

legswitha two-jointedexopod anda three-jointed endopod, the remaining legs with three-jointed rami, the arrange-

ment

ofthe spines andsetae as follows: Second exopod, I

—

0, I

—

1,

II—

5; endopod,

0—1, 0—2, II—

3. Third exopod,

I—

0,

I—

1,

III—

5; endopod,

I—

1,

1—2, 1—3.

Fourth exopod,

1—0, I—

1, II

—

^5;endopod,

—

1,

—

1,I

—

2. Fifth legs two-jointed, the basal joint

much

shorterthanthetermmal andatan anglewiththelatter,

whichistippedwiththree spines ofequallength.

Color a translucent cartilage gray, the ovaries, oviducts, and ex- ternalegg-cases white.

Totallength, 2.45

mm.

Carapace, 0.65

mm.

long, 1.3

mm.

wide.

Free segments, 1

mm.

long. Egg-strings, 1.45

mm.

long.

Male.

—

^General

^body

^{form wider than usual;} carapace trans- verselyelhptical, one-halfAvider thanlong,formingablunt point on eachlateraland on thefrontal margin. Second,third,fourth, and

fifththorax segments the

same

length but diminishing regularlyin

"width, andleaving the wholeof the

swimming

legs visible indorsal view. Genital segment the

same

wddth as the fourth segment, elongate acorn-shaped, with a squarely truncated posterior border and prominent well-rounded posterior corners.

Abdomen

halfthewidthofthegenitalsegmentand

much

shorter, two-jointed,thejointsequal; anal laminaequadrilateral,alittlelonger thanwideand

armed

as inthe female.

Basal portionofthefirstantennaenarrowerandstraighterthanin the female; second antennae and

mouth

parts the

same

except the maxillipeds. These are in normal position behindthe other

mouth

partsandare three-jointed;thesecondjointisstoutwithitsposterior margin swolleninto a

pad

entirelycoveredwith shortspines which increase in size toward thedistal end; the terminalclaw isslender, three-fourths the length of the second joint, slightly curved, and

armed

alongits

umer

margin witha

row

ofminute

saw

teeth,which shut

down

against the spiny pad on the second joint.

S\\imminglegsjointedas inthefemalebutquitedifferentlyarmed;

the basalexopodjoint ofthefirstpaircarriesaverylargeand flat- tened plumoseseta onits outer margin; the terminal exopodjoint of the second, third, and fourth pairs is

armed

with two

medium

spinesontheoutermargin andathird

tmce

thelength, orevenmore, atthetip;thefifthlegsaresmaller thaninthefemalebutsimilarly two-jointed.

Color the

same

butlacldng the white of thefemale rej^roductive oi^ans, so that the male appears considerably darker.

Totallength, 1.10

mm.

Carapace, 0.36

mm.

long,0.52

mm.

wide.

Free thorax, 0.28

mm.

long.

(vcodpoc, slow or sluggish.) ^•

198 PROCEEDINOS OF THE

?fATIONAL

MUSEUM.

vol. 44.

This speciesislarge and fairly

common

in thegill cavities of the little sheepsheads.

But

it is noticeably sluggish in its

movements

and neverleaves thefish on thedeath of thelatter.

On bemg

re-

moved

and placed in an aquarium, it swims but ^little, attaching itselfto one spot and remaining there for a long time.

Even

the male isnot active, and in contrast with otherspecies appears very slow and lazy.

BOMOLOCHUSATTENUATUS,newspecies.

Plate21.

Hostandrecordof specimens

.

—

Threefemales, twoofwhichcarried externalegg-strings,were takenin

company

withArtacolax palleucus onthegillsoftheso-called"poisongrouper," reallyoneofthescor- pionfishes,Scorpsenaplumieri,August_6, 1910.

Type-specimen.

—

^{Cat. No. 43511,U.S.N.^NI. Paratypes, Cat. No.}

42266,U.S.N.M.

Female.

—

^General

^body

^{form veryelongate} andslender; cephalo- thoraxsemielliptical, two-thirdswider thanlong,with almost regu- larcurvature; eye smallandclose tothefrontalmargin.

Secondthoraxsegmentshort,one-seventhnarrowerthanthecepha- lothorax; tliird segment longer and three-quarters as wide as the second; fourthsegmentonlyhalfthelength and widthofthethird;

fifth segment as long as the third andone-fifth narrower than the fourth,formedintoa sort ofneckanteriorlyandposteriorly. Genital segmentbarrel-shaped,the

same

widthasthefifthsegment andtwice as long.

Abdomen

nearly as long as the free thorax

and

genital segment together, three-jointed, thejoints diminishing alittleinlength and width; anal laminae twice aslongaswide,andtwo-thirds the length ofthelastsegment,withsquarecorners.

Each

istippedwitha long innerseta, anouteronehalf as long,a short spineatthe outerdistal corner,andanotheratthe centeroftheouter margin.

Egg-stringsremarkablylongandslenderforthisgenus, aslongas theentire

body

andthe

same

width asthebasal

abdomen

segment, which

makes them

11 timesaslongaswide; eggslarge, arrangedin four longitudinal rows,from25to27ina row.

Firstantennaeverylongandslender,the basal portion only shghtly enlarged and not

much

^curved, but carrying two long tactile setse,

and the usual large plumoseseta at the distal end, pointing back- ward.

Secondantennaelarge

and

stout, the terminaljointtippedwith a longfingerprocess atthe posteriorventral corner, a shorteroneat theanteriorventralcorner,withtwolongandstronglycurvedclaws between them, andalarger curvedclawarisingfromthedorsal sur-

NO. 1950.

CRUSTACEAN PARASITES OF FISH AND CRABS—

WILSON.

199

faceabove thebasesofthetwofinger processes.

The

wholeventral surface ofthejointitself andthat ofthe two processes arecovered withdiagonal corrugations.

The

upperlip isone-halfwiderthanlong,withconvexanterior

and

posterior margins, prominent lateral angles, and a small rounded process at the center of the posterior margin. It is further orna-

mented

onthe ventral surfacewithawideridge,curvinginwardfrom eachlateral angle, thenbackwardto the posterior margin,

and

then inwardagaintothe

median

process.

The

mandibles areturnedbackwardalong theposteriormarginof thelipandterniinate inastraight

and

slenderspine.

The

firstmaxillge are each

armed

with three setse, the two inner ones close together and the

same

length, the outer one

removed

a little

ways

from

them

andonlyone-fifthaslong.

The

second maxillae are rather slender, the terminal joint being inclined forward and endinginasingle

smooth

spine.

The

maxilli- pedshave a triangular basaljoint

and

a stout terminal claw

armed

with a small andslender seta on theinner margin of the proximal curve andalarge accessory spine on theoutermargin of thedistal curve; thebasaljoint carries two stout spinesclose togetherat the center of its inner margin, the anterior one twice the size of the posterior.

The

first

swimming

legs have atwo-jointed exopod

and

a three- jointed endopod; the second, third,

and

fourth legs have three- jointed rami, with the spines

and

setaearranged as follows: Second exopod,

I—

0,

I—

1,

III—

5; endopod,

0—1, 0—2, II—

3. Thirdexo- pod,

I—

0,

II—

1,

II—

6; endopod,

0—1,0—

2,

II—

2. Fourthexopod,

I—

0,

1—

1,

0—5;

endopod,

0—1, 0—1, 0—3.

Colora translucentcartilagegray,oviducts white,egg-strings light gray.

Totallength, 2.28

mm.

Cephalothorax,0.6

mm.

long, 1

mm.

wide.

Free

and

genital segments, 1

mm.

long.

Abdomen,

0.9

mm.

long.

Egg-strings, 2.10

mm.

long.

(attenuatus, very slender, alluding to thefirst antennae, abdomen, andegg-strings.)

Thisspeciesisreadilydistinguished

by

thegreatlengthandslender- nessofits firstantennae, abdomen,

and

egg-strings,

by

thearmature oftheterminaljointofthesecondantennae,

and by

the peculiarshape

and

ornamentationoftheupperlip.

Itis not atalla

common

species, sinceit

was

found ononlyone ofthe

many

scorpionfishexamined; it is,ofcourse,possiblethatthis isnotitsregularhost,butit

was

notfound on

any

of theotherfish examinedduring the seasonof1910.

200 PROCEEDINOS OF THE NATIONAL MUSEUM.

vol.44.

TUCCA IMPRESSUSKr^yer.

Tucca impressusKr0yer,1837, p. 479, pi.5. fig. 2a-f/.

Host and record of specimens.

—

This species wasvery

common

on thefinsof the variouspuffers,

and

almosteveryfishyieldedone or

more

specimensoftheparasite.

Two

lotswere taken fromthe spiny- backedpuffer,Spheroides rnarmoratus, oneon June20, theotheron September 15, and have been numbered, respectively, 42265 and 42269,U.S.N.M.

Two

otherlots were obtainedfrom theburrfish, Chilomycterus antennatus, one on June 15, the other on August 8.

These include

by

far thelarger

number

ofspecimens and also both sexes ofthe parasite, and have been numbered, respectively, 42273 and42251,U.S.N.M.

A

single lotwas obtainedfrom the pectoral finsof theporcupine fish,DiodonM/strlx,and hasreceivedCat.No.42264,U.S.N.M. This lotcontainsfivefemales.

Careful search

was made

on these porcupine fishes for specimens of the distinct species described

by Nordmann

in 1864, asobtained from aDiodonspeciesonthewestcoastof Africa, andto whichthe present author has elsewhere given the

name

verrucosus,^ but none couldbefound.

Inevidence that the habitatofthese(andother) parasitesisexactly restrictedto certainkindsoffish,

we may

note thefactthatalthough this species

was

so

common

onallthepuffers,not asolitaryspecimen

was

ever found on any of the trunkfishes, and yet the latter are always associatedwith the puffers and areverysimilar to

them m

mostrespects.

ARTACOLAXPALLEUCUS, newspecies.

Plates 22and23.

Host and record of specimens.

—

This species was

common

on the gills ofthe"poisongrouper," reallyoneof the scorpionfishes,Scor- psena plumieri Bloch.

Four lots ofspecimens wereobtained from this fish, on June 17,

June 30, July20, and July 21, 1910. These have received respec- tively Cat. Nos. 42272, 42324, 42252, and 42254, U.S.N.M.

Type-specimen.—

A

female, Cat.No.43582,U.S.N.M.

Female.

—

^{General shape} resembling a tadpole, with a large and highly inflated cephalothorax and a long and slender hind body,

made

up of thefifth and sixth (genital) thorax segments and the abdomen.

Head

and first thorax segment fully fused;second, third, and fourth segments partially fused with

them

to form the anterior inflated portion of the body, whichis quite regularly oval ingeneral outline,stronglyarched dorsally,andfilled with theuter-

»Proc.U.S.Nat. Mus.,vol. 39,19n,p. 359.

NO.1950.

CRUSTACEAN PARASITES OF FISH AND CRABS—

WILSON.

201

ine processesof the oviducts.

The

truecephalothoraxforms about two-thirds of this anterior

body

and is one-half wider than long;

thesecond segmentisnarrowedalittleandisquiteshort; the fused thirdandfourthsegmentsareagainnarroweda^little,butarerounded outposteriorlyover thefifth segment,so as to benearly twice the length ofthesecond segment.

A

minute eyeis plainly visible, placed farforward, veryclose to theanteriormargin.

In the hinder portion of the

body

the fifth segment is abruptly narrowed to less tlian half the \vidth of thefused third and fourth segments,andismostlyconcealedindorsalview.

The

genitalsegment is alittlewider thanthefifthsegment ante- riorlywheretheegg-strings areattached, buttapersposteriorly.

The abdomen

is

made

up of three long and narrow segments, diminishing regularly in size, the basal one the

same

length as the genitalsegment.

The

anal laminaeare aslongas theterminalabdo-

men

segment, and each of

them

half as wide, tapering posteriorly andtippedwithaninnerseta aslongastheentireabdomen, anouter one five-eighths as long, and two minutespines at the base

on

the outermargin.

Egg-strings spindle-shaped, slightly swollen at the center, with bluntly rounded ends; each is as wide as the genital segment and as long as the narrowed posterior body; eggs numerous, arranged in six to eightlongitudinal rows, abouteighteenin each row.

Firstantennalongandstout,the basalportionnot

much

enlarged, butfurnishedwithadense

row

ofstoutsetse along theanteriormar- gin.

Between

theseantennae onthe ventralmarginis astout furca pointing backward and composed of two strong spines united

by

a crossbarat their base.

Second antennaslargeandstout, three-jointed, terminal andbasal joints the

same

length, themiddlejointlessthanhalf as long.

The

terminaljointis corrugatedonitsventral surface andtipped witha stoutclaw, aslongasthejointitselfandwellcurved, with abristling

row

ofspinesofvarying lengthsarounditsbase. Mouth-partsclose behind the second antennae; upper lip triangular, one-fifth wider thanlong, arounded angle turnedforwardwhile thelateralmargins are straight; the lateral angles project as rounded knobs and the posteriormarguiisstronglyconvex.

Mandibles simple, turned backward beneath the upper lip and tipped»with a single straight spme. First maxillaarounded

knob armed

with threeplumose setae which diminish in size from witliin outward. Second maxilla short and stout, turned forward and

armed

with asmall spine on theposteriormargin, and tipped with twostraight spines, the innerofwhichistwice thesize oftheouter.

Maxillipeds reachingforward outside the other

mouth

parts nearly

202 PROCEEDINGS OF THE NATIONAL MUSEUM.

vol.44.

to theanteriormarginof theupperlip; theterminalclawlarge and stout,withalongcurvedaccessoryspineonthe outer(distal) curve of the S.

The

basal joints of these maxillipeds are plainly visible behind themaxillae and areconnected across themidline

by

awide sternum.

First

swimming

legswitha one-jointedexopod and a three-jointed endopod; second^ third,andfourthlegswiththree-jointedrami, the spinesandsetaearrangedasfollows: Secondexopod,I

—

0, I

—

1,II

—

7; endopod, 0-^1,

0—2, 1—3.

Third exopod,

I—

0,

I—

1,

0—8;

endopod,

—

0,

0—2,

II

—

^{2. Fourth exopod, I}

—

0, I

—

1,

0—8;

en- dopod,

—

1,

—

1,

—

3.

The

sternal plates connecting the bases ofthethird andfourthlegsarebothonthe fused (tliird andfourth) segment, theformernear theanteriormargin, thelatter atthecenter.

The

fifth legs are uniramose and two-jointed, the terminal joint spatulate andtippedwiththreespines.

Color a translucent cartilagegray, throughwhich thesnow-white uterine processesoftheoviducts

show

prominently; the eggsare also whiteinyoungerstages of development.

Total length, 1.80

mm.

Anterior inflated portion of body, 0.85

mm.

long, 0.75

mm.

wide.

Width

of genital segment, 0.28

mm.

Lengthof egg-strings, 1

mm.

Male.

—

^General

^body

^{form elongate, almostlinear;} cephalothorax spindle-shaped, strongly contracted anteriorly and posteriorly, with the lateral margins projecting. Posterior

body

diminishing

by

halves, thesecond andthirdsegmentsnearly the

same

width,which

is half the cephalothorax, the fourth, fifth, and genital segments halfthewidthof thepreceding two, the

abdomen

halfthe^vidth of thegenitalsegment andtwo-jointed, the basaljointtwicethelength ofthe terminal; anal laminselinearand two-thirds the lengthof the lastjoint.

Appendages similar to those of thefemalewith theusual sexual differences.

The

furca onthe ventral margin between the basesof thefirst antennae is considerably enlarged and its rami overlap the secondantennae.

The

clawsatthetipsofthelatter appendages are also

much

^{enlargedand arebentinto ahalfcircle.}

^The

maxillipeds are tliree-jointed, the second joint enlarged, triangular, and armed with a

row

oflongteethonitsinnermargin; terminalclatvslender, curvedtofit

down

over the secondjoint, beyond^theproximalendof whichitprojects for

some

distance; italsohas a

row

of fine

saw

teeth whichfitagainstthoseonthe secondjoint.

First

swimming

legsnotflattened,as inthe female,butwiththree- jointedramilikethe followingpairs; in the fourthendopod thetwo terminaljoints arefused with only marginal notches to indicate the jointing; otherlegs asinthe female.

NO. 1950.

CRUSTACEAN PARASITES OF FISH AND CRABS—

WILSON.

203

Total length, 1.3

mm.

Cephalothorax, 0.35

mm.

long, 0.4

mm.

wide. Free thorax, 0.37

mm,

long. iVnalsetse, 0.5

mm.

long.

Color as inthe female, the testes, sperm ducts, and sperm recep- taclesshowing snow-white throughthe

body

walls.

(tzcDJ^S'jkoc,TideandXeuKoc,allwliite.)

Thisspeciesisavery

common

oneonthegillsofthescorpionfish, nearlyeveryfishexamined beinginfested.

The

females werefound fastenedtotheskin ontheinside of thegill arches andoccasionally onthefilaments.

The

males were alwaysfastened to thefilaments.

The

hold ofbothsexesisrather aloose one andis easily broken, and theyseemto

move

aboutfreelyover thegills.

When removed

to an aquariumthey fastenreadily to theglass and hold onaswell as tothegills.

They

also

swim

about easilyand quite rapidlyand

may

bekept alive forseveral days.

They

cannot,however, crawl

up

out ^of the water like theCaligidae, but always remain beneath thesurface.

Thisis thefirstmaletobe describedforthe

new

genusArtacolax, and^{it is}interesting tonote

some

differencesbetweenitandatypical Bomoloclius male. These consist chiefly in the anterior marginal furca, thehugeclaws atthe tips of the second antennae, andin the peculiarshape of thesecondjoint and terminal claws of themaxil- lipeds.

PSEUDOEUCANTHUSUNISERIATUS, newspecies.

Plate24.

Host and record of specimens.

—

^A single lot consisting of three femaleswithegg-strings

was

obtainedfromthe

mouth

oftheyellow jack, Caranxcrysos,August 1, 1910.

Type-specimen.

—

^Cat. No. 43510, U.S.N.M. Paratypes, Cat. No.

42256,U.S.N.M.

Female.

—

^General

^body

^form long and narrow; cephalothorax transversely elliptical,one-sixthwiderthanlong; frontalmarginpro- jecting asarounded

knob

betweenthe basesoftheantenna.

Carapace not reaching the lateral margins, its posterior corners prominent androunded, overlapping thesecond thoraxsegment;no dorsal grooves; eye small and situated very far forward, almost between the bases of theantennae. Secondsegmenthalf thewidth of the cephalothorax and very short; third segment a little wider and considerably longer, with projecting posterior corners; fourth segment the

same

width as the second and as long as the third, strongly contracted posteriorly;fifth segment alittlenarrower than the fourth and about half as long, its lateral margins projecting angularly over the bases of the fifth legs; sixth or genital segment the

same

widthasthefifthandtwo-thirdsas long,itslateralmargins stronglyconvex.

204 PROCEEDINGS OF THE NATIONAL MUSEUM.

vol. 44.

Abdomen

abruptly contracted to half the width of the genital segment, three-jointed, the joints diminisliingslightl}^ in width and considerably in length; anal laminae narrow oblong, three times as longaswideand aboutthe

same

lengthasthetwoterminal

abdomen

joints.

Each

lamina is tipped with a large papilla carrying a long and stoutseta,and withfour shortspines,threeatthetipand one onthe outern^argin.

Egg-strings one-sixth longerthan theentire body;eggs large and uniseriate exceptfor a short distance near the basewhere there are tworows,30to35 eggsineachstring.

Firstantennaenot enlargedatthebase,but witha

row

ofwide and flattenedsetaealong theanteriormargin;segmentationindistinctbut apparently

made up

of fivejoints.

Second antennae with a slightly enlarged terminal joint, tipped withafleshy finger-likeprocessand twolongcurvedclaws.

Extending along theanteriormarginofthejointand tothetip of thefingerprocessis a

row

ofblunt teeth;the surface ofthejointis alsocovered with corrugatedridges.

Upper

liplarge and shield-shaped, withprominent rounded ante- rior cornersand a three-lobed posteriormargin. Mandible directed backward and endingin asmooth, needle-like spine. First maxilla with a distinct basal portion and a prominent

knob armed

with three plumose setae, the central one of which is nearly twice the length of the other two. Second maxilla with a long and swollen basaljointcurved forwardtowardtheendand tippedwithtwoshort and stout spinescoveredwithhairs. Basaljoint ofthe maxillipeds partly visible behind the maxillae; second joint curved around the outsideofthesecond maxillaandgreatlyelongatedsothatitreaches infrontof eventhesecond antennae; terminal clawmoderatelybent andfollowing the innermarginofthesecondjoint,withoutaccessory spinesorsetae.

Exopod

of first

swimming

leg turned forward and two-jointed, terminaljoint

much

longerthanthebasal;endopod extending back-

ward

and three-jointed. Second, third, andfourthlegs with three- jointed rami, eachjoint of the exopod

armed

on the outer margin withshort

saw

teethand oneor

more

long spines;arrangementofthe spinesand setae as follows:Secondexopod, I

—

0, I

—

0, II

—

^{3; endo-}

pod,

0—1, 0—2, II—

3. Third exopod,

I—

0,

I—

0,

III—

3;endopod,

0—1, 0—1, 1—3.

Fourth exopod,

I—

0,

I—

0,

III—

3; endopod,

—

1,

—

1, I

—

2. Fifth legs uniramose but wider and longer than anyoftheothers,each tippedwiththreespinesandcarryinga fourth onthe outermargin.

NO. 1950.

CRUSTACEAN PARASITES OF

FISH

AND CRABS—

WILSON.

205

Uterine processesoftheoviductsfillingtheposteriorfourthofthe cephalothoraxandthe second, third,andfourthsegments, sending a branchoutintothebaseofeachofthe

swimming

legs.

Color a dark gray, the cephalothorax nearly transparent, the uterineprocesses snow-white.

Total length, 1.25

mm.

Cephalothorax, 0.5

mm.

long, 0.45

mm.

wide. Free thorax,0.5

mm.

long,0.25

mm.

wide. Egg-strings, 1.5

mm.

long,0.1

mm.

wide.

(uniseriatus, arrangedin asingleseries, alludingto theeggs.)

The

presentgenus

was

created

by

Brianin 1906for

some

parasites which

had

been obtained from the eye of " Clwpea alosa.^'

The naming

ofthegenus

was

unfortunateineveryparticular.

The name

Eucanthus given

by

Claus

had

beenpreoccupied

many

years before foragenus ofcoleopteraand hence cannot stand.

We

thushavea PseudoeucanthusbutnoEucanthus.

Again, Claus's genus

was

distinguished from Bomolochus by the presenceofmaxillaryhooks and

by

thenormalposition ofthe maxil- lipedsbehindtheother

mouth

parts. Brian'sgenusshowsneitherof thesepeculiarities buthas the

mouth

partslikethoseofBomolochus, and might far betterhave been calledPseudohomolochus. Indeed, whileit is easilydistinguishedfrom Eucanthus (Anchistrotos),

what

it really

demands

isa better separationfromBomolochus. This

may

be stated as follows: First antennae neither enlargednorcurved at the base anddestitute of tactilesetse;maxillipedswithoutplumosesetse oraccessoryspines;exopod segmentsofthe second, third,andfourth legs fused and only the terminal joint

armed

with plumose setse;

singleramusofthefifthlegslongerandwiderthananyoftheothers;

each anallaminatipped with asingle-jointedsetaand^small spines;

genitalsegment veryshortandcarryingrudimentarysixthlegs;eggs very large, in two rows only or even mostly uniseriate, forming strings similar to those in the Caligidse and unlike the rest of the ErgasiUdse.

These specimens, obtained and examined alive, enable us to decide allthose points inBrian's original description which needed confirmation or correction.^

1

.

Therearefourfreesegmentsinfrontofthe genitalsegmentas inBomolochus.

The

firstof these, reallythesecond thorax segment,

isvery shortand narrower than the thirdsegment. This segment

isnotindicated inBrian'sfiguresor description.

2. This genuspossessesfirstmaxillae similar to thoseinthe other generaofthe family.

3.

The

specimen figured

by

Brian as a "male(?)" was really a femalewithoutegg-strings.

ISee Proc.U.S.Nat. Mus.,vol. 39, p. 381.

206 PROCEEDINGS OF THE NATIONAL MUSEUM.

vol. 44.

TiENIACANTHUSFLAGELLANS. newspecies.

Plate25,figs.54-61.

Host and record ofspecimens.

—

^Sixfemales with egg-strings were obtained from the gill cavity of the

hammer-head

shark, Sphyrna zygsena, at different times, two being the largest

number

from any singleshark.

Type-specimen.

—

^{Cat. No. 43517, U.S.N.M.} Paratypes, Cat. No.

42261,U.S.N.M.

Female.

—

General

body

form elongate and narrow, especially posteriorly; cephalothorax turned over ventrally so as to stand at right angles to the rest of the

body

axis; ventral surface of this cephalothorax prolongedinto asucking diskwhichprotrudesbeyond

all the

mouth

parts and is surrounded

by

a

membranous

edge, similar to thatonthesuckingdisks ofArgulus.

The

firstantennaelie along the anteriorportionof this edge while thefirstlegscurve aroundtheposterior portion and both no doubt aid inattachingandreleasingthedisk.

Cephalothorax triangularin dorsaloutline, ^vithrounded corners, considerablywiderthan thesecond (firstfree) segment,andentirely covering the antennae,

mouth

parts, and firstlegs. Second to fifth

segments aboutthe

same

lengthbutdiminisliingregularlyinwidth, and showingsuccessivelylargerportions of the

swimming

legs,until thewhole ofthefifthpairappearsin dorsal view. Genitalsegment the

same

widthasthefifthsegment

and

nearly twice aslong,tapering posteriorly.

Abdomen

composed of four segments, diminishing regularly in size,except that thethird oneisalittleshorterthanthelast. Anal laminae narrow, two-thirds the lengthofthelastsegment, each tipped with twosetaeofwhichtheinneroneishalf aslong againastheouter.

Egg-cases attachedtotheanteriorendofthegenitalsegment onthe dorsal surface, their bases covered

by

the rudimentary sixth legs.

Each

caseis aboutthe

same

diameter as the

abdomen

and reaches tothe centeroreventhetipsofthe longest analsetae; eggsnumerous, arrangedin six or seven longitudinal rows, 18 or20 eggsin a row.

Basal portion of first antennae not

much

enlarged, indistinctly dividedinto three parts, with a fringe of large flattenedsetae along the anterior margin; terminal portion

made up

of three distinct segments, heavily

armed

with setae.

Secondantennae three-jointed and tippedwiththree long curved claws, the ventral surface of the terminal joint being corrugated.

Mouth

parts close to the second antennae; upper lip two and a halftimesaswideas long, thetwoanteriormarginsshghtly concave, the posterior one convex. Mandibles three-jointed, the two distal joints bentbackward atan anglewiththe basaljoint; the terminal joint a simplestraight spine. First maxilla

armed

with three setae

NO. 1950.

CRUSTACEAN PARASITES OF

FISH

AND CRABS—

WILSON.

207

ofabout the

same

length. Secondmaxilla tipped with two spines, theposterioronetwicethesizeoftheanterior. MaxiUipeds-wdththe terminaljointbentbackagainstthe basalandtippedwithtwospines, the outer (posterior) ofwhichistwice thesizeoftheinner. Behind the bases ofthe maxillipeds, on either side ofthe midline

and

close toit,is ashortaccessoryspine.

Each

ramus of thefirst legs is two-jointed, those of the second, third, and fourth legs three-jointed, with the arrangement of the spines and setae as follows: Second exopod, I

—

0, I

—

1, II

—

7

endopod,

0—1, 0—2, II—

4. Third exopod,

I—

0,

I—

1,

II—

6

endopod,

0—1, 1—2, II—

3. Fourth exopod,

I—

0,

I—

1,

1—6

endopod,

—

1, I

—

2, II

—

^{3. Fifth} legs two-jointed, the terminal jointenlargedandtippedwithfourspines.

Ovaries in the lateral portions of the cephalothorax^; oviducts extendingbackalong thelateralmarginsofthefreethorax segments, sending out shortandstout uterine processes into each segment.

Colora clear cartilage gray, the ovaries andprocesses white.

Total length, 3

mm.

Cephalothorax, 0.70

mm.

long, 0.98

mm.

wide. Freethorax, 1

mm.

long. Egg-cases, 1.5

mm.

long.

{fiagellans,flagellatingor lashing, in allusion tothe lashingmotions

when

disturbed.)

Thisgenus

was

established

by Sumpf

(1871)

upon some

specimens obtained fromthegillsof Oarcharias {Oarcharhinus) lamia.

A new

species

was

added

by

the presentauthorin 1910 obtainedfrom the vent of the bonnet-head shark, Spliyrna tihuro.

The

present is a third species from the giUs of the hammer-head, and having been studied alive

some

notes can be added on thehabits of the genus.

Allthespecimenswere foundattachedtothe skinofthegillpartitions just outside of the filaments.

When

detached and placed in an aquarium they

swim

about as freely as pelagic forms and

may

be kept alive for several days.

The

ventral disk protrudes like a sucker's

mouth

andisthechieforganofattachment, thusemphasizing oneofthechiefdifferencesbetweenthesubfamiliesoftheErgasilidse.

IntheErgasilinaethereisnoventral diskand attachment^isentirely

by means

of thesecondantennae; intheBomolocliinae there issuch a disk, but the stout claws on themaxillipeds

show

thatthey play an important part in attachment; here in the Tseniacanthinse the ventral disk isfullydeveloped, andis theonly organofattachment, the antennaeand maxilhpeds havingdegeneratedbeyondpractical use.

The

parasites catch onand letgo withgreatease and celerityand adhereto glass as readily as tothefish's giUs.

When

^thus attached thelong thorax and

abdomen

are lashed about actively, especially

upon

irritation, and this peculiar habit^is sure to attract attention to the copepod.

When

the giQs are placed in water the parasites leave

them

quickly and

swim

about, usually without returning to

them

again.

208 PROCEEDINGS OF THE NATIONAL MUSEUM.

toi>.44.

Family

CALIGID7E.

CALIGUSPRODUCTUSDana.

Caligus productusDana,1854, p. 1354, pi. 94,fig. 4.

Hostandrecordof specimens.

—

Thisspecieswasoriginallydescribed

by Dana

from specimensobtained fromthe

common

dolphin, Cory- j)hde7iahippurus, and fromtriggerfishes,Batistes,inthe

West

Indies.

It

was

afterwardnoted

by

StcenstrupandLiitken _(1861, p. 357) as taken from theinside oftheoperculumof thebarracuda,Spliyrsena harracuda, and by Kr0yer(1863, p. 64) asfound on the

same

Cory- phsenaas Dana'sspecimens. Inbothofthese instances thelocality given

was

theDanish

West

Indies.

CALIGUS BALIST^SteenstrupandLtitken.

CaligusbalistseSteenstrup and Lutken,1861, p. 356, pi.1, fig. 1.

Hostandrecordof specimens.

—

Thisspecies

was

originallyobtained fromthe

mouth

andfinsofa

West

IndianBatistes,probablyB.vetuta,

andincludedbothsexes. Ithas notbeen found

by

any subsequent investigators.

CALIGUS ISONYXSteenstru?andLutken.

CaligusisonyxSteenstrupandLutken,1861, p. 358, pi.3, fig. 5.

Host and record ofspecimens.—This species is based on a single femaletaken fromthegillsofagreatbarracuda,SpJiyrsenabarracuda, inthe

West

Indies.

No

otherspecimenhas everbeen obtained.

CALIGUS H.EMULONISKr^yer.

CaligushxmulonisKr0yer,1863, p. 48, pi.4, fig.3a-d.

Hostandrecordof specimens.

—

^{Three specimens,two females and}

a male, of this species were taken from the gills of the yellow grunt, Hsemuton sciurus (H. etegans Cuvier), in the Danish

West

Indies.

No

otherspecimenshaveeverbeenobtained^

CALIGUSTENAXHeller.

Plate26; plate29,figs.99-101.

Caligus tenaxHeller,1865, p. 172, pi. 15,fig.3.

Host and record of specimens.

— The

original type-specimens were obtainedfromthegillsofthe horsecrevalle, Caranxhippos(C. caravr- gusof Heller), in Brazil. Theseincludedfemalesonly. Later(1898) Bassett-Smith reportedbothsexesfromvariousspecies ofCaranxin the Indian Ocean.

Both

sexeswere also obtainedfromthe gillsof Caranxcrysos July 12, and from Caranx ^liipposJuly29, 1910, and havereceivedCat. Nos. 42301 and 42341,U.S.N.M.

Femate.

—

^General

body

formlongandstout; carapace ovate, one- sLxthwiderthanlong,stronglycontracted anteriorly; frontal plates prominent; lunules semicircular,projectinghalf theirwidth; frontal

NO, 1950.

CRUSTACEAN PARASITES OF FISH AND CRABS—

WILSON.

209

marginstraight,deeplyincised atthecenter; lateralareasvery wide;

laterallobes alsowideandshort,curvedstronglyinwardandalmost squarely truncatedatthe ends;

median

lobe alittle

more

thanone- thirdthewidthofthe carapace,withprojectingcornerswhichoverlap thelateral lobes, and an emarginateposterior border.

Eye

minute, one-third the length of the carapace behind the anterior margin.

Freesegment short,two-sevenths thewidthofthe carapace; genital segmentacorn-shaped, three-fourths the lengthandhalfthewidthof the carapace,withwide andbluntlyroundedposteriorlobes.

Abdomen

one-jointed, three-seventhsofthewidthandalittle

more

than half the length of the genital segment; anal laminae minute, widely separated,eachtippedwithfour shortsetae.

Egg-tubesthree-fourthsthewidthofthe

abdomen and

alittle

more

thanhalfthe lengthofthebody.

Terminaljoints ofthefirstantennaeveryslender,

much

longerthan the basaljoints, tentimes aslong aswide. Secondantennae rather slender,witha long terminalclawbentat a rightanglenear thetip.

Maxillary hooks short andnearlystraight, with a stronglyinflated base; first maxillae short

and

triangular, with a small secondary spine near the centerof the inner margin. Maxillipedswitha stout terminalclawfully aslongas themoderatelyinflatedbasaljointand strongly curved. Furca with an exceptionally broad, three-lobed base andthe short rami curvedso as toformtogether ahalfcircle.

First

swimming

legs with a very rudimentaryone-jointedendopod, and with short plumosesetae on the terminal joint of the exopod;

second legs withmedium-sized spines onthe exopod, whose second joint carries an exceptionally wide rowing seta; rami of third legs closetogether, the spineontheexopodlongandstout

and

bentinto a half circle; fourth legs four-jointed with five spines subequal in length.

Cement

glands situated far forward in the genital segment and inclinedoutward,thedivisions oftheglandular portionshowinglike astring ofbeads throughtheircenter.

Color a clear cartilage-gray, very translucent except toward the margin,withtensmallcircularpigment spotsof dark bluish-purple onthe dorsal surfaceofthe carapace, arrangedin pairs.

Total length, 4

mm.

Carapace, 1.75

mm.

long, 2

mm.

wide.

Genital segment, 1.3

mm.

long, 1

mm.

wide.

Abdomen,

0.8

mm.

long, 0.5

mm.

wide. Egg-strings 2.25

mm.

long,0.33

mm.

wide.

2Iale.

—

^{Carapacein allrespectssimilar to that}ofthe female, but proportionally larger; free segment longer and contracted into a neckanteriorlyandposteriorly; genitalsegmentbarrel-shaped,with moderately curved sides andsmall posterior lobes closely approxi-

mated

tothesides oftheabdomen, whichlatterisalmostaswideas

69077°—Proc.N.M.vol.44—¹³ 14

210 PROCEEDINGS OF THE NATIONAL MUSEUM.

vol.44.

the genital segment and indistinctl}^ two-jointed, the basal joint

much

theshorter; anal laminjesmalland circular, each tippedwith threelongsetaeanda shorterone onthelateralmargin.

Terminaljointsofthefirst antennaeevenlongerand

more

slender thaninthe female.

Second antennae with a

much

longersecond joint and a shorter terminal claw, curved into a horseshoe shape. Maxillary hooks longer and

more

slender but straight; other appendages like those ofthe female except thatboththefifthandsixthlegsarepresenton thegenitalsegment, the former onthelateral marginsopposite the spermreceptacles,thelatterformingtheposterior lobes.

Color as inthe female.

Totallength, 2.85

mm.

Carapace, 1.6

mm.

long, 1.7

mm.

wide.

Genitalsegment,0.65

mm.

long,0.45

mm.

wide.

Heller'sdescriptionofthefemaleof thisspecies

was

goodandsuch figures as he presented were excellent, but both were

made

from preserved material alone andlacked

many

details. Bassett-Smith's descriptionof themale isfarfromsatisfactory andhis single figure givesnodetailswhatever.

The

present specimens having been obtained ahve and kept for several days,an attempthas been

made

togiveacomplete descrip- tion from them, particularly with regard to color

and

proportions.

Among

these specimens were two chalimus ^larvae; in the smaller one only thefirstthorax segment

was

fused with thecarapace and the endopod of the first legs was as large as the exopod. In the largeronethefirsttwothoraxsegmentswerefusedwith the carapace and the first endopod

had become

very rudimentary.

Both

sexes

swim

aboutinanaquariumalmost constantlyandare fully as lively as C. rapax.

The

speciesis not a

common

one, for

among

thelarge

number

of jacks examinedduring the season only two were found infestedwith thisparasite.

One

of these, however,yieldeda dozen specimens,which wasanexceptionallylargenumber.

CALIGUSIRRITANSHeller.

Plate25,fig.62; plate27.

CaligusirritansHeller,1865, p. 177, pi. 15,^figs.7and8.

Hostandrecord of specimens.

— A

male and female of thisspecies were obtained from the gills of a large (12 pounds) red snapper, Neomsenisaya, onJuly 22, 1910.

They

have been given Cat. No.

42262,U.S.N.M.

Female.

—

General

body

form long and stout; carapace ovate, longer than wide

and

one-fourth shorterthan therest of the body;

frontalplates prominent, lunules enormous and circular, separated

by

a distance equal to their

own

diameter; lateral areas narrow, lateral lobes curved inward at their tips and bluntly rounded;