I5O NEW YORK STATE MUSEUM 



Conocardium sp. 



Page 50 

 no. 



7 View of a left valve. X3. Rochester (Arey collection) 

 Mytilarca eduliformis sp. nov. 



Page 47 



8-1 o Three views of the type specimen. X2. Lower Shelby bed 

 (N. Y. State Museum) 



Mytilarca acutirostrum Hall (sp.) 



Page 48 



11 Internal cast of a high left valve. Natural size 



12 Another more gibbous specimen, showing the posterior lateral 



teeth. Natural size 



Both specimens are from the Lower Shelby bed (N. Y. State 

 Museum). 



Bellerophon shelbiensis sp. nov. 



Page 51 



13 Ventral view of a specimen, apertural part broken away. 



Natural size 



14 Dorsal view of an internal cast, showing aperture and aper- 



tural emargination. Natural size 



1 8 Lateral view of same specimen, showing cast of umbilicus. 



Natural size 



15 Broken specimen, showing inner volution and umbilical wall. 



X2 



1 6, 17 Two views of a large specimen, showing aperture and dorsal 

 keel. Natural size 



19 View of inner side of volution, showing slit band of preceding 



volution. Natural size 



All specimens are from the Lower Shelby bed (N. Y. State 

 Museum). 



