Two new species of fossil marine shells from California

Vol. 31, pp. 79-80 June29, 1918

PROCEEDINGS

OFTHK

BIOLOGICAL SOCIETY OF WASHINGTON

TWO NEW SPECIES OF FOSSIL MARINE SHELLS FROM CALIFORNIA.*

BY PAUL BARTSCH.

The two

shellsdescribed

below were found

in

a small

collec- tion of fossils collected

by Mr. Thomas _Oldroyd,

at

Nob

Hill Cut,

San _Pedro,

_Cal.,

which was submitted

to the

author

for critical

examination.

At the

_requestof thecollector

they

^are

now

described.

The

_typesof the

two

species are at present ⁱⁿ

Mr. _Oldroyd's

collection^.

Vitrinella thomasi,

new

_species.

.Shell lenticular,

creamy

^white. Nuclear whorls

two and

a _half, well rounded,smooth,scarcelyshowingincremental lines. Postnuclearwhorls one

and

three-fourths, well rounded, with _deeply impressed suture,

marked

_{byvery fine, quite regular} incremental lines only. Periphery strongly rounded. Basevery broadlyopenly umbilicated, ^all thewhorls being^visiblewithin the umbillicus.

The

basal portion^of the whorls is

stronglyrounded

and marked

by incremental^linesonly. Aperture almost circular, slightlyoblique; peristome complete, very slightly notched at theparietal wall.

The

_typemeasures: greaterdiameter, ^1.8

mm.;

altitude, ^.8

mm.

This species suggests ^Vitrinellavrilliamsoni Dall, butthelatteris

much

_larger and_decidedly

more

_depressed.

The

whorlsare

much

broader than_high,

and

the aperture therefore ^is

more

oval in that _species.

Aesopus

^idae,

new

species.

Shell very elongateconic, increasing regularly^insize. Nuclearwhorls decollated. Postnuclear whorls rather high between the _sutures, nar- rowlytabulatedly shouldered ^atthesummit,

marked

_by rather irregular retractivelyslanting^linesofgrowth, which ⁱⁿ the type are rather accen- tuated,

owing

^totheweathering^{of the} specimen. In the type there are

*PublishedbypermissionoftheSecretaryoftheSmithsonian Institution.

22—Pkoc.Biol, Soc.Wash., Vol.31, 1918. (79)

80

Proceedings of thr Biological Society of

Washington

^.

indications of sou^Ipin^re mi _{the spire,} l>nl the specimen ^{is too}

worn

to

make

sureofthis. Base protracted, the anterior portion

marked

by ^the continuation of strong ^{lines of} growth and indications of strong spiral iirations. Aperture oval,decidedlychanneled anteriorly, posteriorangle acute; outer liprather thick; inner lip sigmoid, ^reflected overand ap- pressed ^tothebase; parietalwall covered by^{a thickcallus.}

The

type has seven whorls remaining^(theextremetip being lost) and measures: length, 12.5

mm.;

diameter, ^4.5

mm.

This specimen ^{is the} largestAesopus ^{so far}

known

from the

West

CoastofAmerica.