2d. — A. small broken shell of this species, showing portions of both ears. 

 No. 14, Whitehorse collection. 



2e.— A portion of the lower right side of 2a, enlarged to show the nature 

 of the surface ornamentation. No, 10, Whitehorse collection. 



Aviculopecten oklahomaensis. Page 158. 



3.— A rather small convex valve. The outline of the specimen is faulty, 

 particularly the ear and anterior region. It shows, however, the fact that 

 the ribs are all equal in size except those coming in by implantation. It 

 differs somewhat in its umbonal region from the type figured on the follow- 

 ing plate, and may possibly be a different species. No. 19, Whitehorse 

 collection. 



3a. — Flat valve, probably of this species, nearly complete, showing strong 

 byssal sinus. No. 12, Whitehorse collection. 



36. —The mold of a valve somewhat larger than No. 3, showing the im- 

 pressions, poorly, of the vaulted scales on the ears. No. 20, Whitehorse 

 collec ion. 



3c. —A young specimen of this species and a nearly perfect cast of the 

 left valve. The anterior ear is shown a trifle too large, and the sinus be- 

 low it a little too shallow, thus making the ear extend a little too far down 

 the shell. Ventral outline more rounded than shown in the figure. No. 18, 

 Whitehorse collection. 



Solenomya sp. Page 150. 



4. —View of right valve. One of the two specimens in the collection. 

 No. 22, Whitehorse collection. 



Serpula ? sp. Page 148. 



5.— A minute specimen shown in the mold of a shell. The length of the 

 op of the specimen is little more than ^ mm. No. 126, Dozier collection. 



