New mollusks from the Bahama Islands

NEW MOLLUSKS FROM THE BAHA^IA ISLANDS.

By Paul Bartsch

Assistant Curator, Division of Molhisls, UnitedStatesNationalMuseum.

Some

time ago theUnitedStates National

Museum

^receivedfrom Mr. G.

W.

Pepper, of Providence,

Rhode

Island, a collection of

Bahama

land

moUusks

for determination.

Among

these shells are several forms which are sufficiently distmct from those heretofore

known

from these islands to merit recognition. I have therefore prepared thefollowmg descriptions and figures.

wShortly after describing these^shells,Ihad the pleasureof visiting the

Bahamas

myself, and was able to

make

large collections there, particularlyon Andros Island,whichisa collectivetermappliedto a

number

of minor keys separated

by

tortuous channels of varying width and depth. Practically each key

exammed,

no matter

how

small, providmg itbears vegetation, excepting those in the

Tongue

ofthe Ocean, which are at tmiesdashed over

by

waves,ismhabited

by

Cerions of the glans group. Sufficient differentiation has taken place on each key to enable one to distinguish the shells from the different keys.

On some

of the keys a series ofswales separate an equal

number

of

wooded

elevations, eachof which isoccupied

by

a differentraceoftheseshells.

The

question naturally presents itself, to what ^{extentare these}formsconstant?

Do

they representstable races with fixed characters, or are they

contmuaUy

changing in form? It seemsto

me

that our systematic treatmentof thisgroup wiU have to depend upon the answer to these questions, for it

would befolly to waste time and paper in describing thousands of forms if they arenot constant. If theyare changing, the question

stillpresentsitself, do they passtlirough a definite cycle ofchanges?

Then

thefurtherquestionarises, are

we

dealing withacomplex

Men-

delianproblem?

At

aU events it seems desirable to study the un- derlymg factors responsible for the

phenomena

as they are repre- sented, anduntilsuchstudieshave been completeditwould be

more

desirable tostop indiscriminatedescription of

new

species of Cerlon.

I have probably a hundred so-called species which I might de- scribe,ofrecentyears' collecting, as distinct asanythathavereceived

names

in the past, which will wait for their designation until the

ProceedingsU.S. National Museum,Vol.46-No.2016.

108 PROCEEDINGS OF THE NATIONAL MUSEUM.

vol.46.

breeding experiments^*I

am now

conducting on the Florida keys, under the auspices of the Department of Marine Biology of the Carnegie Institution ofWashington, D. C, have been completed.

The

Cerion describedin the presentpaperis as distinct as any of the described species.

Were

itpart of

my

collectingIwouldretain thedescription until the breeding experimentshavegiven adecision

upon

the desirability, yes,thenecessity, ofdescribing thethousands of races which will be found

when

exhaustive collecting will have been donein theBahamas. However, sincethepresentspecieshas beendistributedundertheabovename,it isbestthatitshouldhave a definite status. For the other forms described, no apologies are necessary.

CERION(STROPmOPS)PEPPERI, new^species.

Plate3,figs.1,3,7-12.

Shell cylindro-conic, moderately tapering at the apex, chocolate brown, crossed with slender, veiy retractive,

somewhat

irregular, whitish, axial riblets, between which appear finer lines of growth.

Base rimate, crossed by the continuation of the axial ribs. Aper- ture small, with a white reflected peristome. Parietal wall pro- vided with astrongfold, which isa littleto theright ofthemiddle;

the secondfoldisatthe junctionofthe innerlipandparietal wall.

This species was found

common by

Mr. G.

W.

Pepper, 2 miles south of Mastic Point, Andros Islands, Bahamas.

The

type, Cat.

No. 250217, U.S.N.M., figure 10, has 12 whorls and measures:

length, 31.0

mm.,

diameter, 9.0

mm.

With

the typelotare a

number

ofsmallerspecimenswhich havea completed aperture, but a

much

lesser

number

of whorls, figures 9 and 12.

They

agree in all characters with the species excepting sizeand

number

ofwhorls.

One

ofthesehas nine whorlsand meas- ures: length, 19.9

mm.,

diameter, 8.2

mm.

Another having nine whorls measures: length, 19.0

mm.,

diameter9.5

mm.

Stillanotherlotof specimens,of which Ihave seen three, figures 1,3,and 11,areintermediatein sizebetweenthesetwo. Thesethree have a second lip, starting from within the firstperistome, building out a

new

growth and leaving the oiigmal refiec^ted peristome as a broadvarix.

One

of these has ten and one eight turns and measures; length 22.9

mm.;

diameter 10.0

mm.

It wouldseem as

if these smaller specimens indicated a forced maturity owing prob- ablytotheeffects ofadryseasonandthat with the returnoffavor- able conditions these three have started a

new

growth.

Still two other specimens of this species have, probably owing to

some

injurj^, assumed a scalariform spire in the later whorls.

These two, figures 7 and 8, were collectedon a small

unnamed

key south ofMasticPoint, Andros Islands, Bahamas.

'SeeYearbook, CarnegieInstitution,No.U,pp.^129-131,andthesecondreport inthenext yearbook, not yetissued.

NO. 2016.

NEW MOLLVSKS FROM THE BAHAMAS— BART8CH.

109

CEPOLISMAYNARDIELEVATA, newsubspecies.

Plate3,figs.4-6.

Shell similar to ^C. maynardi, but

much more

elevated, with the axial sculpture a little more ^strongly emphasized, the individual whorls are more inflated, the aperture is considerably shorter and tendstoward asubcircular ratherthan an ovaloutline. Lip edged with pinkinternally. Color bandsabsent.

Eight specimens of this species were collected

by

Mr. Pepper at MasticPoint, AndrosIslands,

Bahamas. Two

of these, cotypes, are intheU. S.National

Museum,

Cat.No.250221. Thesehavefive whorls and measure: Altitude, 9.8

mm.,

and 10.2

mm.;

greatest diameter, 12.5

mm.

and 13.1

mm.,

respectively.

LEPTINARIABAHAMENSIS,newspecies.

Plates,fig.2.

Shell elongate-conic,yellowishwhite. Whorlsseven,well rounded butnotinflated,

marked by

veryfine,slender, sinuous, axial threads.

Sutures strongly constricted. Periphery of the last whorl well rounded. Base narrowly umbUicated. Aperture oval; posterior angle obtuse; half the outer lip, immediately below the summit, inbent and at the

same

time slightly protracted into a faint claw- likeelement; innerliprevolute, provided witha fold alittleanterior toitsmiddle. Parietalwallglazedwitha thincallus.

The

type. Cat. No. 250220 U.S.N.M., wascollected

by

Mr. G.

W.

Pepper at Mastic Point, Andros Islands, Bahamas. It measures:

Length7.1

mm.;

diameter3.7

mm.

VARICELLAGRACILLIMA BAHAMENSIS,newsubspecies.

Plate3, fig.13.

Shell similar to V. gracilliina, but having the whorls lessinflated,

and scarcely at allshouldered at thesummit, and the sutures

much

less constricted.

The

ribs also in the presentform are very poorly developed and

much more

distantlyspaced than in V.gracillima.

The

type, which has nine whorls, measures: Length 7.5

mm.;

diameter2.0

mm.;

itandthreespecimens.Cat.No.180661, U.S.N.M., were collected

by Owen

^{Bryant on}

Mangrove

Cay, Andros Islands, Bahamas. Cat. No. 180660, U.S.N.M., contains six specimens, which are alittlesmallerin every

way

than the typelot, collected

by

the

same

gentleman under leaves and busheson a hillside near Fort Charlotte, Nassau,

New

Providence. StiU another specimen wasdeterminedforMr.

G.W.

Pepper, collectedonAndrosIslands.

EXPLANATION OF PLATE

3.

Figs.1, 3,7-12. Cerion (Strophiops) pepperi.

4-6. Cepolismaynardielevata.

2.Leptinariabahamensis.

13, Varicellagracillimabahamensis.

U.S.NATIONALMUSEUM PROCEEDINGS, VOL. 46 PL.3

New Mollusks from the BahamaIslands.

Forexplanation of plate see page 109.