Description of a new genus and species of bivalve from the Coronado Islands, Lower California

Vol. XXIll, pp. 171-172

December

_29,

1910

PROCEEDINGS

OF THE

BIOLOGICAL SOCIETY OF WASHINGTON

/

DESCRIPTION OF A NEW GENUS AND SPECIES O BIVALVE FROM THE CORONADO _ISLANDS, /^

LOWER CALIFORNIA. ^

BY WILLIAM ^H.

^I)

ALL.*

During ^a

collectingtrip

made from San _Diego

totiie

Coronado

Islands

by

^Dr.

Fred Baker and Miss

J.

M. Cooke

quite a

number

of

minute

sbells

were

_obtained,

which were submitted

to

me

for

examination. Among ^them

^isa

^small

^bivalve,

^{with an}

^internal

ligament, which can not

be referred to

any recorded genus.

Bernardina

gen. iiov.

Shellsmall,^ofthe generalformofRochefortia, concentricallyscnlptnrcil externally, with a conspicuous prodissoconch, which is elevated in the center

and

atthe margins

and

betweenthese points

somewhat

excavated;

pallial line entire; hinge with the posterior dorsal

margin

^{of the} right valve fitting intoashallow groove ^{in the}

margin

^of the opposite valve;

anteriorly with_{a strong}leftlateral _fittingbetweentwo prominent ^flexu- ous right anterior laterals;

two

_right

and

threeleftcardinalswith the resilium posterior ^to

them

^all.

Hinge

formula, exclusive ^of laterals, L. rlOlOl

R. rOlOlO

The

type^isB. bakeri_sp.nov.

The

_genusis

named

in honorofthelate F. Bernard,of Paris, to

whom we owe

so

much

^of our knowledge ^{of tjie} developmentalhistory^ofthe bivalve hinge.

Bernardina

bakeri _sp. nov.

Shell small,short-ovate, white,with _sculptureof fineregular concentric grooveswithwiderinterspaces^; moderatelycompressed^;

umbones mod-

eratelyelevated,capped

by

the prodi.ssoconchs^; internalmargins smooth, the posterioradductor scar _larger; hingeas de.scribed under _{the genus,} withnoexternal ligament; texture^of the shell porcellanou.'^

and

rather solid. Length,2.8; height, ^l.ii; diameter, ^1.0

mm.;

^thevertical of the beaks behindthe middleoftheshellabout one-ninththetotal length.

*BypermissionoftheDirectorof"theU.S. Nat.Museum.

4C—Proc.Biol. Soc.Wash..Vol.XXIII,1910. (171)

172

Dall

— A New

^Bivalve

_from Louer

California.

Near

the South

Coronado

L-^land, in three fathoms, collected by ^Dr.

Fred Baker, ^after

whom

^{it is}named.. _Types,U.S.Nat.

Mus.

No._220,0!)!».

Cotypesⁱⁿ

Baker and Cooke

collections.

This genus^differsfromtheLeptonacea byhaviufj the internal resilium behind the cardinals as in the Astartacea, ^towhich group ^it probably belongs. In the structureof the hinge^itsnearest neighbor^isthe genus

Cuna

_Hedley, Ijut thelatterissufficiently different in detail torequireno specialcomparison.