355 



Van Winkle on Mollusc a 



9 



Long. 9 mm. ; alt. 8 mm. 



From material collected by Axel Olsson in 1920. 



Genus PTEROPSIS Conrad 

 Pteropsis harrisi n. sp. PI. 1, Figs. 12, 13. 



Description. — Shell very thin and fragile, probably 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 only 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 normally have. The concentric sulci are very much like 

 those of P. lapidosa Con. ; P. harrisi may be only a variety *of 

 lapidosa or possibly the same species, but that can be decided 

 only by more material. 



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

 right valve (the left valve only of the type of the genus having 

 been figured) we believe it worthy 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 1st lanthina expedition 

 in '97. 



Genus CORBULA Bruguiere 

 Subgenus ANAPTERI8 Harris & Van Winkle 



Anapteris Harris & Van Winkle, Bull. Am. Pal. 1919, 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- 



