1420 BULLETIN 92, .UNITED STATES NATIONAL MUSEUM. 



Family CH/Enocardiid.^: Miller. 

 Megambonia Hall. 



Family Conocardiid^e Neumayr. 

 Conocardium Brown. 



Family Lyrodesmid.e Ulrich. 

 Lyrodesma Conrad. 



Family Pectinid/E Lamarck. 



Aviculopecten McCoy, ?Pal8eopteria Whiteaves, Ptorinopecten Hall. 



Family ModiolopsiD/E Fischer. 



Aristerella Ulrich, Colpomya Ulrich, Coralhdomus Whitfield, Cymatonota Ulrich, 

 Endodesma Ulrich, Eurymya Ulrich, Eurymyella Williams, Goniophora Phillips, 

 Modiolodon Ulrich, Modiolopsis Hall, Modiomorpha Hall, Orthodesma Hall and 

 Whitfield, Orthonota Conrad, Parallelodus Branson, Prolobella Ulrich, Psiloconcha 

 Ulrich, Pyanomya Miller, •Sphenolium Miller, Whiteavesia Ulrich. 



Order Anomalodesmacea. 



Family Pkoladellid-E Miller. 

 Physetomya Ulrich, Rhytimya Ulrich. 



Order Teleodesmacea. 



Family Cycloconchid/E Ulrich. 

 Allodesma Ulrich, Anodontopsis McCoy, Cycloconcha Miller. 

 Family Pleurophorid^e Dall. 



Cypricardinia Hall. 

 Prolncina Dall. 

 Ilionia Billings. 



Family Lucinid^e Fleming. 

 Family Pal^eanatid^; Miller. 



POSITION UNCERTAIN. ■ 

 Orthonotella Miller. and Faber (Crustacean?). 



Class AMPHINEURA. 



Order Polyplacophora, 



Family Gryphochitonid^: Dall. 

 Priscochiton Dall. 



Class GASTROPODA. 



Order Aspidobranchia. 



Family Acmeim: Dall. 



Archinacella Ulrich and Scofield, Conchopeltis Walcott, Helcionopsis Ulrich and 

 Scofield, Hypseloconus Berkey, Metoptoma Phillips, Palseacmaea Hall, Scenelb 

 Billings. 



Family Tryblidied/E Pilsbury. 



Tryblidium Lindstrom. 



Family Cyrtolitid^e Ulrich and Scofield. 

 Cyrtolites Conrad, Cyrtolitina Ulrich, Microceras Hall, Trigyra Raymond. 



Family Sinuttid^e Bassler. 

 Bucanella Meek, Sinuites Koken. 



