355 Van Winkle on Mollusc a 



Long. 9 mm. ; alt. 8 mm. 



From material collected b}' Axel Olsson in 1920. 



Genus PTEROPSIS Conrad 

 Pteropsis harrisi n. sp. PL i, Figs. 12, 13. 



Description. — Shell XQxy thin and fragile, probabl}' subovate 

 in shape ; surface covered with wavy, regular undulations which 

 terminate, on the posterior margin a short distance anterior to 

 the extremity of the margin, in a ridge which extends from the 

 beaks ventrad ; anterior dorsal portion inflated, bearing slight 

 traces of the undulations. 



The onh^ specimen we have of this species has the ventral 

 portion broken, the anterior margin is slightly crushed, giving 

 that region an appearance of greater inflation than we believe it 

 would normall}^ have. The concentric sulci are very much like 

 those of Z'. lapidosa Con.; P. harrisi ma}^ be only a variety of 

 lapidosa or possibl}^ the same species, but that can be decided 

 onh' by more material. 



The hinge of this species is so well preserved and being a 

 right valve (the left valve only of the t5^pe of the genus having 

 been figured) we believe it worthj^ an illustration. A small 

 amount of matrix had to be left in the anterior region to act as 

 support for the crushed portion of the shell above. 



From material collected on the ist lanthina ex.pedition 

 in '97. 



Genus CORBULA Bruguiere 

 Subgenus ANAPTERIS Harris & Van Winkle 

 Anapteris Harris & Van Winkle, Bull. Am. Pal. 19 19, Vol. 

 8, p. 7- 



Description of right valve. — Shape and ornamentation as in 

 the left valve, exhibiting on the posterior end the characteristic 

 flare or wing. The ridge which bounds the wing has a narrow 

 groove which extends along the posterior side of the ridge from 

 the umbonal region to the posterior ventral margin, a correspond- 



