1422 BULLETIN 92, UNITED STATES NATIONAL MUSEUM. 



Order Opisthobranchia. 

 Suborder Pteropoda. 



Family Cavoliniime Fischer. 

 Coleoprion Sandberger, Styliola Lesueur. 



Family Hyolithid^ Nicholson. 

 Hyolithea Eichwald, Matthevia Walcott, Pterotheca Salter. 



Suborder Conulariida. 

 Family TentaculitiDjE Walcott. 

 Tentaculites Schlotheim. 



Family Torellellid^e Holm. 

 Coleolus Hall, Hyolithellus Billings, SaltereUa Billings. 



Family Conulariida; Walcott. 

 Conularia Miller, Sphenothallus Hall. 



Class CEPHALOPODA. 

 Subclass Tetrabranchiata. 

 ' Order Nautiloidea. 



Family Endocerattd;e Hyatt. 



Cameroeeras Conrad, Cyclendoceras Grabau and Shinier, Endoceras Hall, Narthe- 

 coceraa Hyatt, Nanno Clarke, Suecoceras Holfn, Vaginoceras Hyatt. 



Family Piloceratid;e Hyatt. 



Clarkoceras Ruedemann,? Cyrtocerina Billings, Piloceras Salter. 



Family Cyrtendoceratid^e Hyatt. 



Cyrtendoceras Remele. 



Family Ascoceratid.<e Barrande. 



Ascoceras Barrande, Glossoceras Barrande. 



Family Mesoceratid^e Hyatt. 

 Billingsites Hyatt. 



Family Orthoceratid/E McCoy. 



Baltoceras Holm, Geisonoceras Hyatt, Orthoceras Breynius. 



Family Cycloceratice Hyatt. 



Cycloceras McCoy, Dawsonoceras Hyatt, Orygoceras B-uedemann, Protocycloceras 

 Hyatt, Spyroceras Hyatt, Kionoceras Hyatt, Protokionoceras Grabau and Shinier. 



Family Tarphyceratid,e Hyatt. 



Aphetoceras Hyatt, Barrandeoceras Hyatt, Deltoceras Hyatt, Enrystomites Schroder, 

 Tarphyceras Hyatt. 



Family TrocholitiD/E Hyatt. 



Apsidoceras Hyatt, Discoceras Barrande, Gyroceras Dekoninck, Litoceras Hyatt, 

 Mitroceras Hyatt, Pycnoceras Hyatt, Schroederoceras Hyatt, Trochoceras Barrande, 

 Trocholites Conrad, Trocholitoceras Hyatt, 



