Descriptions of new forms of mollusks from Alaska contained in the collections of the National Museum

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PROCEEDINGS

OF THE

UNITED STATES NATIONAL MUSEUM.

1878.

I>ESCRII»TIOIVS

OF KE^V

FORITIS

OF

MOI.r.USK» FROITS

ALASKA CONTAIIVED

IIV

THE

COIiLECTIOlVS

OF THE

^{IVAXIONAI^}

MSJSEUiyi,

By

^"W.

H.

UAL.L..

CHITONIDJE.

Genus AMICULA

Gray.

TypeA,vestiiaSowerby.

Subgenus Chlamydochiton

^Dall.

Ch.t. ^Amiculce^similiter sedbranchiaeambientes.

Type Chiton amiculatuaPallas.

Amicula properbas the branchiae median.

Genus LEPTOOHITON

Gray.

Leptochiton Belknapi Dall,n.s.

L.t.elongata,,valdeelevata,dorsualiterangulata;albidaplusminusve cinereo et nigro tincta; valvis elevatis, apicibus distinctis; mucrone centralicouspicuo; sculptura utin L. alveolo, sed granulis in areis dor- sualis sparsim etquincuucialiter dispositis; valvaposticasubapice con- cava, postice sinuata; zona

minima

spiculistenuibus versus

marginem

munita. Lou. 10, lat.3™™. Div. 90°.

^a&.—

North Pacific Ocean, in lat. 53°08'

K, and

Ion. 171° 19' W., atadepth of 1006 fathoms, black sand

and

shells. Brought up in the sounding-cup, on the sounding expedition of the United States ship Tuscarora, Capt.GeorgeE. Belknap, TJ. S. N., in 1874.

This specimen comes from a greaterdepth than

any

specimen of the orderhitherto collected. ItisnearesttoL.alveolus Sars,fromthecoast of Norway.

Genus TEACHYDERMON

Cpr.

Subgenus Traohyeadsia

Cpr. (Ms.).

Trachydermon, valvis centralibus bi-seu pluri-fissatis.

TypeChitonfiilgeirumReeve.

Trachyradsia aleutica Dall,n.s.

T. t.parva,rufo-cinereii, oblonga,fornicata;jugo .icutissimO;

mucrone

Proc. Nat. Mus. ⁷⁸ 1 I

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2

PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM.

submediano, apicibus promineutibus; areis lateralis iuconspicuis; tota superficie quiucuncialiter minute reticulata; intus,valv. aut.10-, post.

11-, centr. 2-fissatis; deut. parvis, perspougiosis, late separatis; subgrundis spongiosis, curtis; sinu parvo; zona squamulis minutisobsita.

Lon. C, lat. S""™.

Sab.

— Western

Aleutians, near low-water markj Dall.

This bears no

marked

resemblance to any of the other

Alaskan

species.

Genus TONICELLA

Cpr.

TypeChitonmarmoreusFabr.

Tonicella saccharina Dall,n.s.

T.t. parva, oblonga, tota superficie saccharina, rufo et albescente picta; mucrone submediano,inconspicuo; areislateralis inconspicueele- vatis,albescentis; areisdorsualissanguinosis,i&qnequiucuncialiter lente reticulatis; v. ant. 10-11-,v. post. 8-10-,v. centr. 1 fissatis; dent, parvis spongiosis, sinu parvo; subgrundis spongiosis, mediocris; zona coriacea ut in Tonicellw aliis: branchia?mediffi. Lon. C.5, lat. 4™"".

j3a&.™^Aleutian Islands, three to thirteenfathoms; Ball.

Thisspecies hasthelustre of rock-candy,

and

is well

marked by

the contrastof the whitelateral with thereddorsal areas.

Genus SCHIZOPLAX

^Dall.

Testa etzona Tonicellw simulans; valvre centrales sulco jugali medi- ano, antico arguteinciso); branchiaj subambieutes.

Type Chiton Brandtii Midd.

For

thisremarkable Alaskan form, distinguished from all otherChi- tons

by

its slit central valves, I propose to adopt a

name

suggested byDr.Carpenter,who, on Middendort'sfigures,

had

intendedto j^ropose it as a subgenus of Tonicella,

The

specimens-obtained by

my

party

seem

to be the first found since the original oneswere obtained.

A

careful examination of the softparts shows thatin dentition

and some

otherdetailssufficientbasis forgeneric separation isfound, confirming the testimonyof the valve characters.

The

sulcus is usuallyfilled

by

a horny or cartilaginous deposit.

It

may

be added here that investigation of the characters of the radulain

numerous

speciesand generaof Chitons inthe National

Mu- seum

shows a very remarkable uniformity of dentition.

No

^larger

groupsthan generaare indicatedin the whole order, which,itappears, can hardly comprise

more

thanonefamily; anditis doubtful ifthiscan bedivided intosubfamilies

by

anycharacters yetelucidated.

The

dentitioninallspeciesexaminedhastheformula G^• 2^•1 ^•2^• 6, or

-

—

.

Of

the te«th, the rhachidian appears always simply cusped;

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PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM.

3

the twolateralspresent varied characters; the third uDciuus,counting outward, isusually spatulate; while theremainderare mere bosses,or scales.

The

widedifferences found in the few figuresof the dentition of Chitons extantappear to be dueto erroneous interpretation of the objectsrepresented.

The

figuresof

Loven

arethe mostsatisfactory.

rOSTPIilOCElVE

FOSSIL.SIIV

THE COAST BAIVOE OF CAI^IFORNIA,

By

"W, II.

DAL,L.

The

National

Museum

has received from Mr. G. F. Merriam, of

San

Luis Eey,Cal.,specimensof

Donax

cali/ornicus,Chionesuccincta, Olivella biplicata,au(l Cerithidea sacrata,in asemi-fossilized condition.

The

first

mentioned retaineda considerable part ofitspinkishinteriorcoloration.

These fossils (probably with otherspecies) are stated by Mr.

Merriam

to befoundin greatabundance at thehead of acahon in that vicinity, inthe heart of theCoast Range, twelve miles from the sea in adirect line,

and

sixhundredfeet above tide-water. All thespeciesare found living in

abundance

on the present sea-coast. This indicates a very recent elevation for this part of the coast, if the facts are correctly interpreted,

and

further specimens

and

details will be awaited with interest.

NOTES ON TnE AMERICAN SPECIES OF

TIIE

GENUS

CYBIUItl.

By FELIPE POEY.

[TranslatedbyG.BrownGoode,fromMS.memorandumofProfessorFelipe Poey.J

Cybium caballa,Cuv.

&

^Val.

Cybium cahalla, Cuvier

&

Valenciennes, Histoire Natnrelle des Poiesons, viii,18:51,p.187.

—

Guntiier, Catalogueoftbe Acantboi)terygian Fishesin the Collectiouof the BritishMuseum,ii,1860,p. 373.

—

Poey,Repertorio Fisico-NaturaldelaIsladeCuba,i,1867, p.322; ii,p.13^;audinSynopsia PisciumCubensiuiu,op.cit.,ii,p.362.

CyUumacervum,Cuvier

&

Valenciennes,Ioc. cit.,p.186 {neeti/puii).

Vulgo^:

—

Sierra.

Differential Characters.

—

First dorsal with fourteen spines, without a blaclcspotanteriorly.

Body

immaculateintheadult, spotted with yel- lowish in the

young

fish.

The number

of teethincreases with the age; inlargespecimens,it is If.

The

larger teeth are placed upon the middleof the jaw, those in thelower

jaw

being atriflethe longer.

Tbe

lateral lineisvery sinuous upon the posterior portion of the body.

The

eyeislarger than in Cy- biumregale.

Bluish

upon

the back, whitish under the belly. First dorsal white;

second dorsal andcaudal dusky-bluish {hlen-noiratre)_; pectorals bluish, as is also the anal, which, however, becomes white at its extremity

;

ventrals whitish.