104 



BULLETIN 111, UNITED STATES NATIONAL MUSEUM. 



Locality. 



Off Cape Lookout, North Carolina, U. S. F. C 

 Station 2612. 



do 



Off Beaufort, North Carolina, Eolis Station 21.. 



Cape Lookout, Bight, North Carolina, Eolis Sta- 

 tion 20. 



Cape Fear, North Carolina, U. S. F. C. Station 

 2619. 



Fryfaig Pan Shoals, North Carolina (John Ford, 

 collector). 



Off Miami, Florida, Eolis Station 69 , 



....do 



Miami, Florida, Eolis Station 52 



Off Turtle Harbor, Florida, Eolis Station 58 



Off Key West, Florida, Eolis Station 42 



Tortugas (southwest channel), Florida, Eolis 

 Station 36. 



Tortugas (southwest channel), Florida, Eolis 

 Station 33. 



Off Mobile Bay, Alabama, U. S. B. F. Station 

 2389. 



Cape San Bias, Florida (Gulf), U. S. B. F. Sta- 

 tion 2369. 



West coast, Florida 



Remarks. 



52 fms., 67°, crs. wh. s. 



Do. 

 6-9 fms. 

 3 fms. 



15 fms., crs. yl. s. rot. co. 

 12.1 fms. 



38 fms. 

 Do. 



50 fms. 

 60 fms. 

 10 fms. 



16 fms. 



27 fms., gy. s. brk. 

 26 fms., crs. gy. s. sh. 

 30 fms. 



PLATYSCHIDES, new subgenus. 



The shell has two or four apical slits, which are broad and shallow, 

 causing the resulting lobes between them to be low and wide. The 

 type of the subgenus is Cadulus grandis Verrill. For enlarged drawing 

 of apical characters of Platyschides, see plate 18, figure 13. 



This group differs from Polyschides in the greatly reduced promi- 

 nence of the apical features. The slits often amount to no more than 

 what would appear to be chipped-out portions of the margin of the 

 apical orifice and having between them small, sometimes pointed but 

 always inconspicuous lobes, or these apical slits may be only very 

 small notches. In a few species of this subgenus the apical features 

 become so reduced it is difficult or even impossible to refer them 

 with certainly to it. Unfortunately, injuries to the delicate apical 

 rim often confuse the characters or obliterate them entirely, but 

 perfect specimens of this group usually show clearly enough their 

 characters. Platyschides occupies a middle ground between Poly- 

 schides and Gadila, the latter group having no modification of the 

 simple circular rim of the apical orifice. I can not claim for Platy- 

 schides any great value as a biologic subdivision, but merely as a 

 convenient means of grouping a number of species under a fairly 

 constant character. 



All attempts at making satisfactory or even useful keys to the 

 species have been abandoned as confusing rather than helpful. Even 

 grouping them under their finer specific characters does not seem to 

 be very successful. 



The following five species may be placed side by side by reason only 

 of their very large size: Cadulus grandis, C. elephas, 0. spectahilis, 

 C. poculum, and C. aequalis. 



