Vol. 31, pp. 79-80 June 29, 1918 



PROCEEDINGS 



OF THK 



BIOLOGICAL SOCIETY OF WASHINGTON 



TWO NEW SPECIES OF FOSSIL MARINE SHELLS 



FROM CALIFORNIA.* 



BY PAUL BARTSCH. 



The two shells described 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 request of the collector they are now described. 



The types of 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, scarcely showing incremental lines. Postnuclear whorls 

 one and three-fourths, well rounded, with deeply impressed suture, 

 marked by very fine, quite regular incremental lines only. Periphery 

 strongly rounded. Base very broadly openly umbilicated, all the whorls 

 being visible within the umbillicus. The basal portion of the whorls is 

 strongly rounded and marked by incremental lines only. Aperture almost 

 circular, slightly oblique; peristome complete, very slightly notched at 

 the parietal wall. 



The type measures: greater diameter, 1.8 mm.; altitude, .8 mm. This 

 species suggests Vitrinella vrilliamsoni Dall, but the latter is much larger 

 and decidedly more depressed. The whorls are much broader than high, 

 and the aperture therefore is more oval in that species. 



Aesopus idae, new species. 



Shell very elongate conic, increasing regularly in size. Nuclear whorls 

 decollated. Postnuclear whorls rather high between the sutures, nar- 

 rowly tabulatedly shouldered at the summit, marked by rather irregular 

 retractively slanting lines of growth, which in the type are rather accen- 

 tuated, owing to the weathering of the specimen. In the type there are 



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



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



