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



PROCEEDINGS 



OF THE 



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. Postnnclear whorls 

 flattened, slightly excurved at the narrowly shouldered summit, marked 

 by decidedly obsolete axial ribs, which are too feeble to permit counting 

 and numerous closely spaced spiral striations. The summit of the suc- 

 ceeding turns falls very slightly anterior to the somewhat angulated peri- 

 phery, and gives the whorls an overhanging appearance. Suture strongly 

 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; 

 outer lip thin; inner lip slightly curved, revolute, appressed to the base 

 only at the expanded portion of its insertion, the rest free; parietal wall 

 covered by a thin callus. 



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 the first postnuclear turns. The nine and a quarter turns 

 remaining measure: length, 6.4 mm.; diameter, 1.9 mm. 



* Published by permission of the Secretary of the Smithsonian Institution. 



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



