PSEUDOPOTAMILLA FROM THE

FIVE

NEW

SPECIES OF

PSEUDOPOTAMILLA FROM THE

PACIFIC COAST OF

NORTH

AMERICA.

BY

J.

PERCY MOORE.

A noteworthy

portion of the Polychseta collections of the

Alaskan Salmon Commission

of 1903 is seven species, five of

which

areherein described as new. of the genus Pseudopotamilla recenth^ established

by

Miss Bush.

These new

species are of interest in indicating the interrelations of Pseudopotamilla

and

^other genera into

which

the former tends to grade. In

most

respectsP.intermediais

most

typical,

and

stands

between

theotherspecies,

which may

be

grouped

incouples

having

quite distinct affinities.

On

the one

hand

P. hrevihranchiata

and

P. occelata approach Eudistyliain the structure of thecollar,

and

theformerespecially intheuncini

and

thelatterinthe

numerous

eyes

and

general habit. Neither of these, however,

shows any

indication of spiral coiling of the branchial bases,

which

are small

and

simple.

On

the otherhand, P. splendida

and

P. anoculata

have

the angulated branchial stems without eyes

and

the

more

elongated spatulate tho- racic setfe

which

characterize Parasahella

and

Sabella, but the dorsal collar lobes are exceptionally well developed

and

the branchial bases are very small

and

simple.

The

first three species

have

the avicular uncinioftheposterior thoracicsegmentsenlarged

and

otherwisepecu-

liar,in thisrespectresembling P. oculiferaLeidy.

Pseudopotamilla brevibranchiata^sp.nov. PLXXXVII,figs.1to7.

A

^{speciesremarkablefortheshortness ofits branchise}

^and

^{the con-}

spicuousness of its eyes.

Two

specimens containing nearly

mature ova measure

55

and

58

mm.

long

and have

128

and

151 segments respectively.

Of

this length the palpi

and

branchial

crown measure

only6 to 6.5

mm. and

the thorax8

mm. Owing

to thecontraction of the

abdomen

the

form

is rather short

and

stout, but the posterior _-J tapers in the usual

way

to the small pygidium,

which

bears a close aggregationof small

brown

eyespots dorsal tothe anus.

The

palpi or branchial bases arevery firm

and

rigid, not at all pro-

duced

^ventrally nor spirally twisted,

though

slightl}- inflected

and winged

^; thedistal

margin

iseven

and

^transverse

and

the heightuniform (about 1.5

mm.)

all round.

The

dorsal free

margin

bears a rather prominent, rigid, slightly incvuved

wing which

overlaps its fellow

36

^56 PROCEEDINGS OF THE ACADEMY OF

[July, medially

and

is separated

by

a deep,

narrow

incision

from

a similar butthinner

wing

borne

upon

the baseofthedorsalmost_branchialstem.

Including a

few rudimentary

ventral ones

and

several in process of regeneration at other points, the

number

of branchia varies

from

29 to _31.

^

Owing

to excessivecrowding

some

of

them

are forced inward, producing

an

appearance of

two

series.

The

stems or radioles are re-

markably

short, stout, rigid

and

brittle and, without considering the

rudimentary and

regenerating ones, increase gradually inlength

from

ventral todorsal, thelatterbeing about i^longer

than

fullvdeveloped ventral ones.

Although

theouter faceisround, thebasal J^{orso, dis-} tally to the position ofthe first eye, bears a pair of very low lateral

wmgs

or margins

which

are united for a very short distance at the base.

Beyond

this point the stems are laterally compressed.

The

barbs arealso thick

and

brittle, closelytwo-ranked,

and

all short, the longest proximal ones not exceeding 3 times the diameter ofthe

stem and

the distal ones being

much

shorter. A\rhen _fully developed they continue nearly to the end, leavingfree ashort thick tip only.

Eyes

are exclusivelyinoneseries

on

thesideofthe

stem

nearest tothedorso-

median

line.

They

are

deep

purplish-brown

and

very conspicuous,

and

confined to azone comprising the middlehalfofthe branchiaj,

but most

irregularlyarranged

on

individual branchiie,

on which

they

seldom occupy

the entire

width

of the zone,

though

they

may

be variously scattered, or

crowded

intooneor

more

groups.

The

usual

number

has 4 ^or 5, but varies

from

2 to _9,

and

they

may

equal ^ the diameter of the

stem

orbe minute, scarcely_visible specks,

and

all or

any number may

belarge or small.

A

high oral

membrane

with rumpled, sinuous margins begins ven- trallyatthe_{sides of} the

mouth,

isreflected

on

itself

and

passes

around

theinternal bases ofthebranchias to

become

continuous dorsallywith the large,

much

folded, foliaceous_tentacles.

The

peristomialcollar differs considerably

from

thestructm-e typical ofthegenus,asexemplified

by

P.reniformis

and

P. oculifera,

and

indi- cates the

method

of transition

between

forms with the collar lobes widely separated

and

_{those with}

them

incontactdorsally.

The

dorsal portion consists of a pair of very

low

folds reflected into the dorsal fissure

and

there

coming

into contact.

These

are continuous with the remainderofthecoUar

which

risesabruptlyinto a pairof

rounded

lobes just

above

the collar _setae.

From

this point it is high

and

regular to near the

median

ventral region, M^here a

wide open

notch

on

each side partly separates the slender, pointed ventral lobes

which

are divided

from

each other

by

the

deep

ventral fissure.

Besides the peristomiiimthere are S setigerous thoracic somites,"alI uniannulate

and

separated

by

deep segmentalfurrows.

The

regionis

nearly cylindrical, butslightly depressed

and from

3 to 3.5

mm.

wide.

The

8ventralglandular plates, including thefirst, areall transversely oblong

and

the second

and

third only are divided transversely into 2 equal halves.

Abdominal

somites are also uniannulate

and

the pos- terior ones

much

crowded.

Thick

ventral plates are developed throughout the region

and

are divided into halves

by

a

deep

faecal

grooveextending

from

the anustothefirst

abdominal

segment,cutting thelatteroblic^uely to the right

and

entering the thoracico-abdominal fm-rowinfront ofthesetae, then appearing againfaintly in the dorsal mid-lineofthethorax

and

enteringthe dorsal fissure.

Thoracic parapodia are strictly lateral

and

the uncinigerous tori flush with the surface, while the setigerous tubercles

may

project slightlyor be retracted within little pockets.

The

collar setse

form

a verysmall tuft

and

the remaining 7 fascicles are

somewhat

elongated laterally

and

oblique.

On

^all thoracic somites the uncinigerous tori areseparatedventrally

by

_{about ^}

and

dorsally

by

nearly or quite h the

body

circumference.

They

increase in length gradually to the third

which

equals the ventral interspace, then decrease to the last

which

isf ^ofthelongest,whilethefirstequalsthefifth or sixth.

As

thetori shorten the setae tufts, closely

approximated

to their dorsal ends,

assume

a correspondingly lower position.

Abdominal

parapodia are

more prominent and

distinct lateralelevations,highest at theposition of the setsD tufts neartheir ventral ends.

The

anterior tori are, like the thoracic ones, nearly flush with thesurface

and

are consequently transitional, but, like all of the others, they are separated

from

the ventral plates

by

a deep longitudinal groove.

Both

setae

and

uncini are in strictly vertical, linearseries.

On

the first

abdominal segment

the former has alength ofabout + thatofthesetaDtuft,

and

thelatter equals the uncinigerous torus ofthe last thoracic somite.

From

this point both gradually diminish inlength

and number

of setae oruncini tothe caudalend.

At

thedorsalend ofeachthoracic

and

theventral end of each

abdominal

torusis asmall, eye-like

pigment

spot.

In thecollar tuftallsetaeare capillary,winged, lanceolate, the ven- tral ones, however,shorter

and

with widerwings

than

thedorsal.

On

theremaining thoracic somites the setay areof

two

sorts;a fewin the dorsal

and

anterior part of the fascicleresemble thecollar setae (fig.

1), the

number

of

which

decreases

from

anterior segments backward.

Those

intheventral

and

posterior portions of thebundle

form

a

com-

pact

phalanx

of several rows of obovate paddle-shaped or spatulate

558

PROCEEDINGS OF THE ACADEMY OF

[Julj, setffi with miicronate tips

and

the broad blades curved

and

often slightly asymmetrical (fig. 3).

Abdominal

setse are all capillarywith theshaft bent atthe widest portion ofthe short double asymmetrical blades.

They

are arranged in

two

verticalrows,those inthe anterior

(fig. 2) having verylong, attenuated,

smooth

tips, the posterior

much

shorterbut otherwise similar. Their

number

varies

from

24 in ante- riorto4 or 5 in posteriorfascicles. All setae are distinctlystriated.

Thoracic tori bear avicular uncini in the posterior

and

pick-shaped setse in the anterior rank, the

number

of each

on

somite

VI

being 65

and on IX

40,

The

^{former (fig.} 4)

have

a rather long slender base,

narrow but prominent

breast, thick erect neck,

and

little

expanded

head, with the prominent,finelydividedcrest

pushed

wellforward

and

its frontal

margin

forming a perfectly straight profile with the acute beak,

which

is justperceptibly bent forward at thetip.

On

the pos- teriorthoracic somitesthe uncini are

somewhat

larger,

but

thediffer- enceisnotso greatasinP.occelata

and

P. intermedia; the

neck

is also

more

craned forward

and

there are otherslight peculiarities.

The

lat- ter(figs.6

and

7)

have

slender,finelystriatedstemsslightlycurved near theend,

and expanded

intoa coarsely striated

head

enclosed in asheath inflatedatthebase,

and

prolonged nearlyat right angles tothe

stem

into a moderately elongated slender process.

Abdominal

tori contain avicularuncinionly(fig.5),smaller

than

thethoracicuncini

which

they resem.ble in

many

respects,

but have much

the

form

of the

wooden

decoys used in

duck

shooting.

Except

forthe caudaleyes, the

minute

spots at theends ofthe^tori

and

a trace of

brown

on the

median

dorsal portion of the collar,

no pigment

exists

on

thebod}'',

which

isofapale yellowishcolor.

On

one

specimen

the basal half of the branchial

wreath

has

no

pigment, but inthedistalhalf are fourpartly coalescent

bands

ofbrown, not extend- ing on to the

back

of the stems,

but

deep-colored on the sides of the latter

and

thebasal half ofthebarbs.

Wlien

thebranchise are

opened up

the barbs ofthe concealed branchiae are

found

tobe of a beautiful orangeinthoseparts

from which pigment

isabsent.

The

secondspeci-

men

has very little

pigment showing on

the exterior except

narrow

longitudinal streaksof

brown on

thebranchialbase corresponding with the intervals

between

branchiae.

When opened up

the distal half of thebranchiae

shows

tracesoforange

on

thebarbs, while the basal half

is ofa nearlysolid orange brown.

The

tubesareratherthick,

tough and horn

l^rown,

and

arethickly covered with fine sand; the free

end

is collapsible for a considerable distance.

Thisspeciespresents

an

interestingcombinationofcharacters'

which weaken

one'sfaith inthe

adequacy

of

some

recent generic definitions.

Indeed,itisdoubtful

whether

thisspeciesshould not gointothe'genus Eudistyla.

The

entire structure ofthe collar agrees closelywith Miss Bush's description of the organ in that genus; the uncini

and

^setae are almost counterparts,

and

Johnson's figures of those of Eudistyla (Bispira)polymoiyha, with

which

the preliminarydeterminationassoci- atedthesespecimens,

would answer

almostequally wellforthepresent species.

The

eyes

and

thedorsalwings ofthepalpi orbranchiarbases are also features of similarity.

But

the absence of

any pronounced

ventral prolongation ofthebranchial bases

and

thetotalabsence ofa spiraltwist tothelatter,inthewriter's Ofjinion,

more than

overbalance those

more

trivial characters.

The

shortness of the branchiae

may

suggest the possibility of their having been injured

and

in process of regeneration,but acarefulstudy hasbroughttolight

many

reasonsfor

rejectingthis view. ^•

The

type

and

co-type

were taken

July 11, 1903, atstation 4,247 in

Kasaan Bay,

Prince of

Wales

Island,in 95-114 fathoms, ina

bottom

of

mixed mud, sand and broken

shells.

Pseudopotamillaoccelata ^sp.nov. PI.XXXVII,figs. 8to14.

From

the other species describedin this paper thepresentis distin- guished

by

itsgreatlength

and numerous and

conspicuous eyes.

The

type measiu-es 130

mm.,

of

which

the branchiae are 18

mm. and

the thorax 11

mm.

long.

A

^still larger

specimen from

the

same

station

isnearty20

mm.

longer.

The

branchial bases arestiff,high

and

prominent,ofuniformheight, provided dorsally with notched wings,

and

ventrally with a slightly involute thin

membrane.

Full-grown specimens possess 21 to 24 pairs of branchiae, small ones 60

mm.

long

from

17 to 20.

They

are moderatelylong, thedorsal

somewhat

exceeding the ventral,

and

en- tirely without a connecting

membrane. The

stems are rather stout,

rounded

externally

and

provided with a slightly raised line

on

each

margin

justexternal to thebases ofthe barbs.

The

latter arerather short

and

well separated

toward

the base of the stems, but near the distal

end become

very slender, aboutthreetimes as longas thebksal ones

and much

crowded, leaving a very short thick tip of the

stem which

also bears

minute budding

barbs ofdecreasing length almostto the

extreme

end.

Very

conspicuous aretherich

dark brown

eyes,

which

areveryuni-

form

insize

and

large(about ^ the diameterofthestem), elevated

and

bulging; all are

on

the

margin

oftheexternal surface that^lies nearest

560

PROCEEDINGS OF THE ACADEMY OF

[July, to'thedorso-medianline

when

thebranchiae are spread. They'exhibit the usual irregularityin arrangement,

but on

theventral branchiaj all are situated

on

the proximal ^

and on

thedorsal

on

the proximal!half of the stem, except that

on

the

two

dorsalmost they are

evenTmore

extensively distributed.

The

ventralstems

commonly

bear5 or6'eyes, occasionally as

few

as 3, usually distant or in couples.

On

thedorsal half ofthe circle of branchise each shaft bears

from

7 to 12, even the latter

number

being exceeded

on

the dorsalmostpair.

Except

that theyareusually

much crowded

proximally,theyarearranged similarly to the ventralones.

As

in P. brevihranchiata the collar is intermediate in

form between

that of Eudisiyla

and

typical Pseudopotamilla.

The

dorsal lobes are broadty

rounded and

slopecaudally

from

theiranterior

median margin

intothe dorso-lateralincision;

but

theyare so largelyunitedwith the dorsal'surface ofthe thorax

upon which

they restthat only theouter portion is free,

though

to a greater

depth than

in P. brevihranchiata

.

The

lateralportionsrise abruptlyas

prominent

lobes justdorsal tothe collar setae,

and

then continue of nearly even height until they rise directlyintotheelongated

narrow and

pointed ventrallobes.

Palpal

and

oral

membranes

of the usual

form

are present

and

the tentacles

have

alength

about

equal tothe breadthofthethorax, their basal half being

broad and

foliaceous

and

the distal half slender

and

cirriform.

As

aresult ofhaving

been

preservedinthe tubesthe

body

isslender, elongated

and

nearly cylindrical throughout, only a very short region at theposterior

end

being tapered tothe pygidium, while the anterior thoracic regionisslightly depressed.

Probably

as aresult ofpressure inthetubes,the

segments

areveryfaintlyseparated, except along the glandularventralplates.

Except

posteriorlytheyarerather long,the anterior

abdominal and

the thoracic onesbeing

from

-}toh aslong as wide.

The pygidium

isoblique,with

two

pairs of

minute

lobesguard- ingthe anuslaterally

and sometimes

a

group

of

numerous

small

brown

specks

on

each side above.

Normally

there are 9 thoracicsegments, of

which

8are setigerous,

though

one

example

has

but

7.

The abdomi-

nalsegments

vary from

125

on

a

specimen

60

mm.

long to187

on

the largest example,

measuring

148

mm.

All ofthe ventral plates are narrow,

nowhere

exceeding ^the

body width and

^usually

much

less

than

this. Corresponding tothe

form

of the segments the

extreme

posterior ones are

4

times as

wide

as long;

throughout

most

ofthe length ofthe

abdomen

they aretAvice as

wide

as long;

and

those ofthe anterior

abdominal and most

ofthethoracic

1905.]

NATURAL

segmentsare square, only thefirst3 ofthelatterbeing again wider

and

irregular.

Except on

the ^collar the thoracic seta tufts are oblique

and

^linear, nearly half as long asthe correspondingtori,

and

each

guarded by

a conspicuous anterior

and

posterior fold. Tori are relatively short, little exceeding h the distance separating

them

ventrally,

and

of

remarkably

uniformlength, the second beingslightlythe longest

and

those following decreasing inlength to thelast.

On

the

abdomen

the uncinigeroustori

and

thesetaetufts^lieinnearly the

same

line,thelatter veryslightlyin

advance

ofthe former

and

butlittle shorter.

The

ffecal grooveiswell

marked

throughout both thorax

and

abdo-

men and

passes obliquely across the right side of the ^first

abdominal and

last thoracic segments for their entire length.

Collar setffi are all of one form, capillary, acute, curved, narrowly double-winged, not very long.

The

remaining thoracic fascicles are

composed

ofasmall dorsal

group

ofcapillarysetsesimilartothosejust described (fig. S)

and

alarge

number

of broad-bladed spatulate setse (fig. 10), forminga close

phalanx

ofseveralvertical rows.

Abdominal

setge are arrangedin

two

verticalrows (about 15 ineach

on XX),

the one withshorttips, the otherwith

them ^more

^slender

^and

about twice as long ^(fig. 9).

Koth have

theirshafts abruptly bent at the ^surface of the body,

where

they are provided with short striated wings of unequal width,

beyond which

projects thelong, slender, acutetip.

Thoracic tori contain the usual tAvo forms of avicular uncini

and pennoned

seta, of

which

there are ofeach about 45 ineachtorus of

V

and

30

on

IX.

On

anteriorsegments the former

have

the

form shown

infig. 11, except thatthe

beak

is usuallystraighter.

The body

^islong

and

straight,the^Ijreast moderate, the

neck

rather short,

head

large

and

crest

prominent and

^{wellforw^ard.}

On

the^{last thoracic}

segment

the uncini (fig. 12) arevery

much

larger

and

of quite differentform, the

body

being very long

and

slender, the^breastvery small, the neck ratherlong

and

sloping forward,the

head and

crestsmall

and

the

beak

less sharply bent

downward.

Anterior

abdominal

tori bear about 40 uncini(fig. 13)

which

arem\ichsmaller

than

thesmallestofthethoracic

and

characterized

by

the small ^size of theposterior i)ortion of the body, the large breast,

and

exceeding high

and

full crest.

The

pick- shapedor

pennoned

seta(fig. 14)

have

shortstems

and

slightlyenlarged heads with the usual

hood and

prolongedtip.

Besides a slight tinge of

brown

about the parapodia, and,

on some

specimens, 4to 6 pairsof

brown

spots,diminishingin size posteriorly,

on

the

dorsum

ofII to

V

or^TI,thereis

no pigment on

thebody.

On

562

PROCEEDINGS OF THE ACADEMY OF

[July, thebranchiaethere isusiiall}- a narro\\'

band

of dull])urplish-1:)rown

on

the branchial bases

and

3 zones of rich ]3\irplish-bro\vn

on

the basal half of the branchiae, tlie lower

two

of

which sometimes

coalesce to

form

aA^ery broad zone covering the entire occelated region.

On

the alcoholic specimens this color verylittle involves the outer surface of thestems, butis deep

on

theirinner surfaces

and

the barbs.

On

one

specimen

the barbs of the basal half of the branchine are also largeh^

orange

and

the

pigment

of each eye extends as a

narrow

oblique line inaproximaldirection

halfway

acrosstheouter surfaceofthestem.

The

tubesof this speciesoccur,

sometimes

singlyattached to stones,

sometimes

in

clumps

of several

wound among

one anotherin

an

intri- cate fashion

and

firmly united.

They

are thick, of cartilage-like con- sistency after preservation

and

usually little encrusted with sand or other foreign substances.

In

onecasetheattachedsurfaceofthe tubes

is

much

infiltrated with calcareous matter.

Specimens

occur off Fort Rupert,

Vancouver

Island (station 4,202), in25-36 fathoms,

on

a

bottom

ofgray sand^;inIcj'Strait(station 4.261), in 10 fathoms,

on

a

bottom

of

mud and

rock;

and

at

Afognak

Island (stations 4,269

and

4,270), in 14—19 fathoms,

on

a

bottom

ofhard sand with rocks.

The

last station yielded tlie largest specimens,

among them

the type.

Pseudopotamilla intermediasp.nov. PLXXXVII,figs.15to 22.

Of

this well-marked species the type alone is

known.

This is a female filled with eggs

and

having a total length of 58

mm.,

of

which

thebranchia3 are 3

mm. and

the thorax7

mm. The

thorax is 2

mm.

and

the anterior part of the

abdomen

2.5

mm.

wide.

There

are 158 somites, 10 (9setigerous) of

which

are thoracic.

Most noteworthy

isthesmallsizeofthebranchiae,the

extreme

length of

which

is only 3

mm. The

entire absence of

pigment and

the rela- tively pale color of the eyes suggests the possibility of their being in process of regeneration.

The

branchial ])ases are remarkal^ly small, of soft texture,

have

the distal

margin

evenly transverse, the ventral

margin

truncate

and

notat allelongatedorspirally coiled,

and

the dor- sal

margin

provided with anotched lappetas inP. brcvibrayichiaia,

but

smaller

and

soft

and meml^ranous

insteadofrigid.

Each

palpusbears 12 branchiae, including 2 or 3

rudimentary

ventral ones.

The

longest areonly 3times theheight of thebase,

and

only alittle

more than

_-Jof the lengthofthethorax. In

arrangement

theyarestrictlyone-ranked,

and none

is

crowded

into the interior.

The

stems are rather stout,

roimded on

the external face

and

lack altogether marginal wings

and

connecting

membranes. The

barl^saretwo-ranked,distributed rather

sparsely,thelargestabout4timesthediameterofthestem,diminishing inlength

toward

the end, leaving a short thicktip of the

stem

naked.

Never more than

2 eyes,

and sometimes

one or none, occm- on each stem.

They

arerather small, palebrown,regularin

arrangement and

always

on

theproximalhalf

and

thedorso-median aspect of thestems ofthespread branchise.

The

oral

membrane and

tentacle areslightly developed, thelatter folded longitudinally.

In

most

respects the collar is typical of the genus.

The median

dorsal portionis better developed

than

in P. hrevibranchiata, but less so

than

in P. oculijera (Leidy); thelateral portions are rather promi- nent, rising abruptly

from

just

above

the collar seta^,

and expanding

ventrally in broad,

prominent

lobes separated

by

the

median

ventral fissure;

on

onesidea deepnotch,

on

the other aslightone

bounds

the ventral lobelaterally.

The form

is generally slender

and

cylindrical, the thorax slightly depressedanteriorly,narrower

than

the anterior regionofthe

abdomen,

theposterior halfof

which

tapers verygently to thepygidium,

and

the anus nearly terminal but

surmounted by

a small lobe bearing

two

groups of

minute brown

eye-spots.

Thoracic setigerous tufts are prominent, the anterior especially elongated

and

oblique.

The

uncinigerous tori areverylittle elevated

above

thesurface, thefirst

and

second longest, equalling about ^ the circarnferenceofthe

body and

separated

by an

equalventral distance.

From

the second they decrease inlength, the lastscarcely

more than

J^ofthefirst

and

separated

by

a ventral distanceof about ^ ^ofthecir-

cumference.

Abdominal

parapodia are rather prominent, especially theventral setigerous ends,thefirstabout equaltotheeighth thoracic

and

succeeding ones decreasingslowly but steadily to thelast.

The

ventral glandular plates are

narrow on

the

abdominal

region, separated

from

the parapodia

by

wide grooves

and

completelydivided intoapairofsquares

by

thedeepfaecalgroove,

which

turns totheright obliquely acrossthefirst

and

appears again

on

the

dorsum

oftheante- riorpartofthethorax,

where

itopensintothe dorsalfissure. Itisnot visible

on

theposteriorpartofthethorax.

The

thoracicventral plates areindistinct

and

poorly developed inthetype.

No pigment

ispresent

on

the greaterpartofthebody, beingconfined to4 pairs ofdiscretereddish-brownspots

on

the

dorsum

ofsomites II to V,

which become

successively smaller

and

the last

mere

specks.

Owing

tothe presence ofgreat

numbers

ofeggsthe

abdomen

is

some- what

yellowish.

All setae

have

a pale yellow color.

Those

in the collar tuft are,

564 PROCEEDINGS OF THE ACADEMY OF

[July, like the succeeding thoracic tufts, of

two

kinds.

A

few of the dorsahiiost arecapillary,

more

or lesssigmoidly curved

and

narrowly winged.

The

ventral ones,

more numerous and

arranged in several parallel rows, are of the mucronate-spatulate type, but

have

a

somewhat

narrower

and

longer obovate blade

than

those

on

the fol-

lowing somites.

On

remaining thoracic somites the setre are

more numerous,

thecapillary(fig.15)forminga projectingtuft,thespatulate

(fig. 17) in

more and

longer

rows and having somewhat

shorter

and

broader blades

than

those

on

the collar; the

mucronate

^tipislong

and

slender.

Abdominal

setse are in

two

verticalrows, 9 or 10 ineach

row

of the first

few

fascicles

and

4 or 5 in the lessdistinctly 2-ranked fascicles of the caudalend.

Both

kinds

have

the shaftabruptlybent just

beyond

the surface of the body, the longer

form

with a very

narrow

accessory

wing on

the concave side

and

a wider

but

very short

wing on

the

convex

side,

and

the

smooth

acute tip often

much

longer

than

inthe setafigured.

The

shortsetae(fig. 16) aresig-

moidly

curved,

have

shorter,

smooth

tips

and

broader, strongly stri-

ated wingsreflexed

from

the

convex

side.

Thoracic toribear avicular uncini inthe posterior

and

pick-shaped setaeintheanteriorrow.

The

former(fig.18)

have

longstraightbodies, moderate-sized breasts, rather short, erect necks, enlarged heads,

prominent

'crests very

low

in front,

and

curved beaks.

On

the last,

and

possibly other posterior, thoracic somites the uncini (fig. 19) are very

much

larger, with very long bodies,

minute

breast, long

neck

well sloped forward,

head

not enlarged, very small crest

and weak

beak.

Another

less typical one with

somewhat

larger crest is

shown

in fig.20; 43 occur in the 9th

and

60 in the 4th torus,

though

the latter

occupy

twice as long a space.

The

pick-shaped setae

have

the

form shown

in fig. 22, the

heads

being

much

reduced

and

the

hoods much

inflated

and

withslendertips

about

as long as the beaks of the uncini.

Abdominal

aviculae (fig. 21) are

much

smaller

than

the thoracic, with relatively shorter bases, larger breast, short thick neck,

and

crest larger,fartherforward

and

extending low

down on

the beak,

which

has astraightprofile.

One specimen

only

known, from

station 4,267, off

Cape Edgecumbe,

SitkaSound, 922 fathoms,

on

a

bottom

of softgray

mud.

Pseudopotamilla splendida^sp.nov. PLXXXVII,figs.23to 27.

This large

handsome

species is

founded on two

specimens lacking theposterior

end

; wdth the 37anterior segments alonethetype

meas-

ures 65

mm.

long, 27

mm.

belongingto thebranchiie

and

8'

mm.

tothe thorax including the collar, -while the greatest T\idth of the thorax, exclusive ofthesetae, is5

mm.

1905.]

NATURAL

^SCIENCES

^OF

PHILADELPHIA.

The

branchial lobes are very .mall, barely reaching

*;

^{bjcler o;}

the ^{collar, stiff, thick,} very little free, lacking ^all trace of the dorsa

appendag;

^{orlappet of}

some

species; the^ventral end

1--; -'

^ ;^

produced

nor ^involute, without ^{a thin}

membrane, and

^{partly unitrf}

r t

^{fellow of the oppositeside.}

^Twenty-two

^{pairs of}

^{b-chi. ^e}

presentineach specimen.

Except

^{thatthoseof oneside areinprocess}

ofCneration

^{Tilare of} approximately equal ^length

and

are entire

y

separate tothebase.

The

external surface^ofthe stems ^iswider

than

theTnternal ^flattened

and

provided with^{lateral angles} but

no wmgs.

The

e ^is

no

^{indication of eyes.}

The

barbs ^are

numerous and

^closely arrlnged ⁱⁿ2 ranks^; they^{increasein sizeregularly}

from

the base^for

|

tteTen^h

^{of the stem, ihose at the distal}

^end

^{of this}

region being ³ times the length^ofthebasal ones

and

ithe width^ofthe thorax; ⁱⁿthe

liTtal

Tthey

^againdecrease, leavingafilamentoustipequal^totirebasal barbs. Several ^of the ^basal barbs ^of the doi^almost ^{branchiae are}

""ThetnS^l;oiis,

flaring collarhas verylarge dorsal^lobes,separated

by

the ^{dorsal fissire}

and bounded

^laterally

by

^large,

^deep

^incisions

Mdwiy ^between

^{the dorsal fissure}

^and

^{the collar seta,;} these dorso- toteraUncisions ^{are partly filled}

by

a small, thin lobe ^arising

from

the bottom.

The

laterarportion^ofthecollar^risesin

an

^{even curvetotl«}

same

height asthe ^{dorsal lobe, its}

margin

^{is slightly}

wavy bu

not at

Jnotchrf

^nor

^produced

into ventral ^lobes. b"t

— ^-

^b,.adly

rounded below and

^{overlaps the ventral}

fissure

from

both sides

Smembranesare

promi„ent,but^present

no

character, ^{ic^^^^^^}

Th^

tentacles shghtlv exceed the ^{collar in length}

and have

^{a thick}

^l^driMlpering

to a'free end, the ^{basal half} being provided

on

each sidewith

broad

marginsfolded together.

On

^a

^specimen

^{preservedoutsideof}the tube the thorax^isbroad

and

depressed

and

tapers regularly

from

the collar

segment

^{into the}

mor sknder

^{t rete}

abdomen. The

second example, having been

removed

om

a tubeafter preservation, ^is

more

^nearly

^y>'-'-^

*™;^\;^^

Allseomentsarevery^{distinctlyindicated}

and umannulate The

^type

possesses 9 thoracic ⁽⁸ setigerous)

and

28 remaining

abdomma

^seg-

;;°e"ranother specimen

^{has 10thoracic(9}setigerous)

and

58

abdomi-

nal segments,both, ^of course,beingincomplete.

Although

^{the dorsal fissure is}

deep on

the anteuor ^{2 thoiacic se}

metts

^{ftefa^calgrooveisnot}discernible

on

the thorax.

On

the abdo-

Z^ll

^sdeep

^and

conspicuous,

and

^can

be

^traced

around

^{theright side}

rthe

fin.rabdominal

segment

^{until it disappears in the furrow} anterior to the^{set^e.}

566

PROCEEDINGS OF THE ACADEMY OF

[July,

The

thoracic setigerous tubercles

have

short basesbutprojectpromi- nently.

The

tori areverylong,thefirst

about

twice

and

thelastabout 1^ times theventral interspace,theothersintermediate.

On

the abdo-

men

the

same

parts arelittle elevated

and

placed at nearly the

same

level as the dorsal

end

of tlie last thoracic.

The

setigerous line is

shorter

than

thethoracic

and

the firsttorus

about

_jaslongasthelast thoracic.

About

90avicula?

and

the

same mmiber

ofpick-shapedsetae

occur

on

the torus ofIII

and

60 of each

on

IX.

On

the thoracic seg-

ments

thespatulatesetsearevery

numerous and

arrangedin5 or 6 ver- ticalrows,wdiilethecapillarysetse

do

not exceed

about

15.

The

capil- lary

abdominal

seta are in

two

regular

rows

of

about

10 each

on

the anterior segments.

All ofthe collar setae

and

thedorsalmostsetae

on

the other thoracic

segments

are rather short, stout, capillary, tapered to

an

acute tip, little curved

and

with small, nearlysymmetrical wings with very fine oblique strise

on

each side.

The

spatulate setse (fig. 24)

have

stout stems

and

rather long,

narrow

curved blades about 2^ timesaslongas

wide

with apical

arms

of

moderate

length.

The abdominal

setse of

both rows do

not differ greatly in length.

They

are longer

than

the thoracic capillarysetse,especially posteriorly,

and

are gracefullycurved

and

tapered, with fairly broad, oblique, strongly striated

and

nearly symmetrical wings (fig. 23). Avicular uncini are nearly

uniform

in size

and form on

all thoracic segments.

They

^(fig. 25)

have moder-

ately long ciu-ved bodies, full breasts, slender upright necks, elevated crests

and

slender acute beaks.

Abdominal

avicular uncini (fig. 26) are smaller

and have

very small bodies

and

deeperbreastsbutare other- wisesimilar.

The

pick-shaped thoracic setae

have

the

form shown

in fig. 27.

Pigment

is totally absent

from

the

body and on

thebranchiae exists onlyas sixregular,

narrow

zonesofpalereddish-brown,chieflyconfined tothebasalhalvesofthebarbs

and

scarcelyapparent

on

thestems.

The

tubes are nearly straight, thick, pale

brown and

A^ery little incrusted with

sand

or other foreignmatter.

Known

only

from

t\A"o large specimens taken at station 4,245,

Kasaan Bay,

Prince of

Wales

Island,

June

11, 1903, in 9o-9S fathoms,

on

a

bottom

of

dark

green

mud and sand mixed

with shell

and

rock fragments.

Pseudopotamilla anoculata^{ep.nov. pi.}XXXVII,figs.28to 33.

This

handsome

specieshas thebranchial bases exactlyasinP. splen- dida,thatis,theyarevery small

and

concealedbj-thecollar,

somewhat

coalesced ventrally,

and

lackthedorsalla]5pet, ventral

membrane and

any

indication

whatever

of a ventral involution.

There

are 15 pairs ofplume-like branchiae, each very long

and

graceful anfl without

any

trace of

an

interbranchial

membrane. The

stems are

more convex

externally thanthoseofP. sylendida,butstDldistinctly flattened,

and

thereis

no

traceofeyes.

The

barbsareallveryslender,2-ranked, well separated

and

increase regularly in size

from

very short ones at the base to very long ones,

much

exceeding the diameter of the thorax

toward

theend; inthedistal\ they again^decrease,leaving a shorttip entirely free

from

them.

The

dorsal lobes ofthe^collarare

narrow and

verylong, considerably exceedingthesecond

segment

inlength,with nearlyparallel sides

and rounded

ends, the

two

separated

by

a^^idedorsal fissure.

The

dorso- lateral notches are verydeep but

narrow and

not occupied bj^ asmall lobe. Laterad ofthenotches the^collarrisesnearlytothe heightofthe dorsallobes,

which

it

somewhat

overlaps

by means

oflow,broadexten- sions

toward

the

median

line.

The

remainder of the

margin

is

even and

scarcely crenulate, the ventral lobes arisingregularly

and

gradu-

ally, without the formation of

any

notch, into

prominent

triangular lobes overlapping the bases of the branchiae

and

separated

by

a deep

median

fissure.

The

single

example

is fortunately complete. It measures 122

mm.

long,thethorax being15.5

mm. and

the branchiae32

mm.

long,

and

the former 3.5

mm.

^{wide. It} is consequently long

and

slender, tapering tothe

pygidium

inthe posterior ^{-^-.}

There

are 14 (13 setigerous) tho- racic somites

and

162

abdominal

somites.

The

former region is

scarcely depressed

and

the remainder of the

body

nearly cylindrical

from

pressure of the tube. Besides being unusually broad

and

deep anteriorlythedorsal fissureisprolongedintoafaecalgroove extending for nearly the length of thethorax, but gradually fading out behind.

The

thoracic segments _{are ^} as long as wide, the middle

abdominal

about ^^aslongaswide,

and

theposteriorvery

much

shorter. Ventral platesaredeveloped

much

as inP.splendida, but thethoracic arerela- tively longer

and

the lateral notches divide

them

unequally, being nearer totheposteriorborder; theanterior

abdominal

plates aretwice as

wide

as long

and

the posterior 4 times or more, all very thick

and

deeply divided^;

none

ofthe al)dominals arenotchedlaterally,

and

they

occupy

about^ ofthe

body

width.

Thoracic setae tufts are short

and

straight, the anterior ones placed at avery highlevel.

The

tori ofIII

have

alength ofnearly^ the^cir- cumferenceofthe

body and

areseparated

by

^^entrally-J-thisdistance.

From

the first they decrease in size regularly, the last

and

shortest

568

PROCEEDINGS OF THE ACADEMY OF

[J^ly, being

but

_^aslongasthefirst.

The

first

abdominal

torusisnot

more

than h aslong as thelastthoracic,

and

is

on

the level of the thoracic setae tufts.

The

firstthoracictorus bears65uncini

and an

equal

num-

berofpick-shapedsetae,thefifth43

and

thelast 33. Anterior

abdomi-

naltori

have about

25uncini

and

thesetfetufts

about

15setae,lessdis- tinctly in 2

rows than

in otherspecies.

Allofthecollar setae

and

thedorsalmostsetae ofother thoracicfasci- cles are ofthe usual slightly curved, acute, tapering

form

with short, rather narrow, obliquel}^ striated wings

which

arise at

an

angle with the stem.

Not

over about a

dozen

occur in eachfascicle. Spatulate setae(fig. 30) are

much

less

numerous than

inP.splendida,

and

arranged in only2 or 3 vertical rows.

The

wingsaredecidedlylong, the entire

expanded

region being 3 times as long as wide, with

an

apical

arm

exceeding in length itsgreatest diameter.

The

striation of the blade

is unusually faint. Al^dominal setae (figs. 2S, 29) are few (about 15 inanteriortori),notdistinctlyarrangedin

two

rows,

and

the longer

and

shorter ones not greatly different.

The stem

is constricted but not sharply bent at thebase ofthe blade.

Avicular uncini (fig. 31) of similar

form

occur throughout the tho- racic region.

The

base is only

moderately

elongated

and

slightly curved, the breast rather prominent, the

neck

moderately long

and

sloped forward, the crest well forward

and

forming a straight profile with the slender acute beak.

Abdominal

uncini (fig. 32) are

much

smaller, with veryshort bodies slightly curved

downward

posteriorly, the breast

deep and

^full, neck

and

crestsimilar tothoseofthethoracic uncini,

but

the

beak much

shorter

and

smaller.

The

pick-shaped or

pennoned

setae(fig. 33)

have

slightlycurvedstems, elongated flattened heads, verydifficult to see clearly,

and

high compressed

hoods drawn

out at a

wide

anglewith the

stem

into delicate pennants.

No

colorremains except

on

thebranchiae, the ventral ones of

which have

6 or7 richwine-color spots

on

thebarbs

and

slightly

on

thestems.

On some

of the dorsal branchiae these spots coalesce so that they are chieflycolored,withafewirregularwhitespots atthebase

and

a

more

extensivewhiteregion

toward

thetip.

The

tubeis

dark

colored,rough, brittle

and

covered with sand.

This species is

known from

the type only, taken

June

7, at station 4,230, in the vicinity of

Naka

Bay,

Behm

Canal,

on

a rocky bottom, in lOS to 240 fathoms.

Explanation of Plate XXXYII.

(All figuresare magnified250 diameters.) Pseudopotamilla hrevibranchiata,figs. 1 to7.

Fig. 1.

—

Dorsal thoracic capillarysetafromsomite"^'I.

Fig. 2.

—

^{Longabdominalcapillarysetafromsomite}

^XX.

Fig. 3.

—

^{Spatiilatcthoracicsetafromsomite VI.}

Fig. 4.

—

Thoracic avicular uncinusfromsomite VI.

Fig. 5.

—

^{Abdominal avicularuncinus fromsomite}

^XX.

Fig. 6.

—

Pick-shaped setafromsomite VI.

Fig. 7.

—

Another viewof theendofthesame.

Pseudopotamillaoccelata, figs.Sto 14.

Fig. 8.

—

Dorsal thoracic capillary seta fromVI.

Fig. 9.

—

^{Longabdominal} capillary setafrom

XX.

Fig. 10.

—

Spatulate thoracicsetafromVI.

Fig. 11.

—

Thoracic avicular uncinusfromVI.

Fig. 12.

—

Thoracic avicular uncinusfrom IX.

Fig. 13.

—

^Abdominal avicular uncinusfrom

XX.

Fig. 14.

—

Pick-shaped uncinusfromVI.

Pseudopotamilla intermedia, ^figs. 15 to 22.

Fig. 15.

—

Dorsal thoracic capillarysetafromYI.

Fig. 16.

—

^{Shortabdominal capillarysetafrom}

^XX.

Fig. 17.

—

Spatulate thoracicsetafromVI.

Fig. 18.

—

Thoracic avicular uncinusfromVI.

Fig. 19.

— ^A

^{typicalavicularuncinusfromthelastthoracic}somite (X).

Fig. 20.

—

^{Portionofanotherfromthesame torusshowinga}larger crest.

Fig. 21.

—

^{Abdominalavicular}uncinus from XII.

Fig. 22.

—

Pick-shapedsetafrom somite VII.

Pseudopotamilla splendida, figs. 23 to 27.

Fig. 23.

—

^{Longabdominal capillarysetafrom}

^XXI.

Fig. 24.

—

Spatulate thoracic setafromVI.

Fig. 25.

—

Thoracic avicular uncinusfromVI.

Fig. 26.

—

Abdominalavicularuncinusfrom

XX.

Fig. 27.

—

Pick-shapedsetafromVI.

Pseudopotamilla anoculata, figs.28 to 33.

Fig. 28.

— A

sliorterabdominalcapillary setafrom

XXVI.

Fig. 29.

—

^{Faceviewofthebladedportionofthe same.}

Fig. 30.

—

Spatulate thoracic setafromVI.

Fig. 31.

—

Thoracic avicular uncinusfromA^I.

Fig.32.—Abdominal avicularuncinus fromXXA'I.

Fig. 33.

—

Pick-shapedsetafromVI.

PROC. ACAD. NAT.SCI. PHILA. 1905.

PLATE

XXXVII.

MOORE. PSEUDOPOTAMILLA.