184 LOO CHOO MOLLUSKS. 



Cyrena yaeyamensis n. sp.* PI. VIII, fig. 7; pi. IX, fig. 6. 



Shell shorter than the preceding, being less produced posteriorly, 

 the posterior surface not so distinctly angular, posterior truncation 

 less marked ; anterior lateral tooth not so short. Anterior dorsal 

 slope of hinge line straight, posterior dorsal slope slightly convex. 

 Color and sculpture as in luchuana, except that there is usually 

 some oblique corrugation of the posterior slope. Length 75, breadth 

 63, diam. 36 mm. 



Yaeyama Is., Loo Choo group (Frederick Stearns). 



This may prove to be a form of Cyrena papua, or of C. buschii 

 Phil., of China, but it is more triangular, with the posterior margin 

 more produced. 



MYTILIDJE. 



Mytilus crassitesta Lischke.* Yaeyama. 

 Modiola philippinarum Hanley.* 



LIMIDJE. 

 Lima lima Linn.* Yaeyama. 



SPONDYLIDJE. 



Spondylus ducalis Chemn.* Hirama Jima Is. 

 Spondylis sinensis Sowb.* Hirama Jima I -. 



OSTRJEIDJE. 



Ostraea rivularis Old. (?)* Yaeyama. 

 Ostraea cucullata Born.* Yaeyama. 

 Ostraea hyotis Linn. Yaeyama. 

 Ostraea denselamellosa Lischke.* Yaeyama. 

 Ostraea cristagalli Linn.* Yaeyama. 



PTERIIDJE. 



Pteria macroptera Lam.* 



Throughout the Loo Choo group (Stearns). 



Some of the specimens collected attain great size, rivalling M. 

 margaritifera. 



Pteria cochenhauseni Dkr.* (=A. flammata Reeve ? ) Itoma Jima Is. 

 Pteria meleagridis (Spengl.) Chemn.* Itoma Jima Is. 

 Perna (Meleagrina) margaritifera Linn.* Yaeyama. 

 Malleus regula Forsk.* Yaeyama. 



