1 82 



NEW YORK STATE MUSEUM 



The anterior muscular impression is comparatively large and 

 strongly limited on the posterior side. The impression of the strong 

 cardinal tooth is preserved beneath the beak. 



Two specimens measure respectively 20 and 22 mm in length, 

 and 15 mm in height. 

 Remarks. In our specimen it will be noted that the hinge is ve\a.- 

 >%. tively longer than in the above original description, 



^^ ^^ and, if the specimen represented by figure 30 is ex- 

 ^B|M|^^ eluded, the posterior truncated margin is proportion- 

 ately shorter. Including this figure, our specimen is 



The beak appears to 

 Oyster basin. Cof- jjg quite as prominent in the Coffin island specimen 

 and the shell somewhat smaller. 



Schizodus CU-. 



neus Hall' Left intermediate between the two 



valve 



^ 



Schizodus denysi nov. Oyster basin, Coflnn I. 



Schizodus denysi nov. 



Shell small, subrhomboidal, rather compressed. Beaks elevated, 

 pointed. Posterior margin very obliquely truncated ; postventral 

 extremity angular ; ven- 

 tral border convex * 

 throughout. curving 

 more rapidly toward 

 the front; front border 

 convex except for con- 

 striction just in front of 

 beak ; umbonal ridge an- 

 gular. The valves are thickest below the beaks which are well anterior. 

 Surface with lines of increment indistinctly preserved on the cast. 



Dimensions. Length, 12.5 mm; height, 9 mm; length of hinge, 

 12.5 mm. 



Remarks. This shell is related to several :\Iississippic forms. 



It is relatively longer than S. t r i g o n a 1 i s, while the posterior 



margin is more oblique than in shells of the S. w h e e 1 e r i type. 



Both the shell and the hinge are longer than those features in 



S. c u r t i f o r m i s. 



Aviculopinna egena nov. 



Shell small, broad for its length. The hinge appears to be some- 

 what arcuate. Shell widening rather un- 

 evenly along the ventral margin, rather 

 rapidly at first, then more slowly in some 

 specimens. Posterior margin truncato- 

 convex. possibly slightly sinuate in some 

 specimens. Surface marked by wrinkles of growth which are at 

 right angles to the hinge passing directly downward or a very little 



Aviculopinna egena nov. 

 Oyster basin, CoflRn I. 



