A new fossil pyramidellid mollusk from the west coast of America

Vol. 31, pp. 81-82 June ^29,1918

PROCEEDINGS

OFTHE

BIOLOGICAL SOCIETY OF WASHINGTON

A NEW ^FOSSIL PYRAMIDELLID MOLLUSK FROM THE WEST COAST OF AMERICA.

BY PAUL ^BARTSCH.*

Turbonilla

(Pyrgolampros) amava, new

^species.

Shell elongate^conic. Nuclear whorls decollated. Postnnclearwhorls flattened, slightlyexcurved at thenarrowly shouldered summit,

marked

bydecidedly obsolete axial ribs, whichare toofeeble topermit counting

and numerous

_{closely spaced} spiral striations.

The summit

^{of the} suc- ceeding turns^falls veryslightly anteriorto the

somewhat

_angulatedperi- phery,

and

gives thewhorls an overhanging appearance. Suturestrongly impressed. Periphery^{of the last}whorl _{feebly angulated.} Base short, well rounded,

marked by

^fine incremental lines

and

exceedingly ^fine spiral striations only. Aperture rhomboidal; posterior angle obtuse;

outerlipthin; innerlipslightlycurved, revolute, appressed ^to the base only ^atthe

expanded

portion ^ofitsinsertion, therest free; parietalwall covered by^athincallus.

The

_{type; Cat.} No. 325612, U. S. N. M.,

comes

from the lower San Pedro series of

Dead Man's

Island, California. It has lost the nucleus,

and

_probably thefirstpostnuclear^turns.

The

nine

and

a quarter turns remaining measure: length, 6.4

mm.;

diameter, ^1.9

mm.

*Publishedbypermission^oftheSecretaryofthe SmithsonianInstitution.

•23—Proc.Biol. Soc.Wash.,Vol.31, 1918. (81)