1420 BULLETIN 92, UNITED STATES NATIONAL MUSEUM. 



Family CH^NOCARDIID^ Miller. 

 Megambonia Hall. 



Family CONOCARDIID^E Neumayr. 

 Conocardium Brown. 



Family LYRODESMID^E Ulrich. 

 Lyrodesma Conrad. 



Family PECTINID.E Lamarck. 



Aviculopecten McCoy, ?Palseopteria Whiteaves, Pterinopecten Hall. 

 Family MODIOLOPSHXE Fischer. 



Aristerella Ulrich, Colpomya Ulrich, Corallidomus Whitfield, Cymatonota Ulrich, 

 Endodeema 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 PHOLADELLID^ Miller. 

 Physetomya Ulrich, Rhytimya Ulrich. 



Order TELEODESMACEA. 



Family CYCLOCONCHID^: Ulrich. 

 Allodesma Ulrich, Anodontopsis McCoy, Cycloconcha Miller. 



Family PLSUROPHORID.E Dall. 

 Cypricardinia Hall. 



Family LUCINID^ Fleming. 

 Prolucina Dall. 



Family PAL;EANATID;E Miller. 

 Ilionia Bilh'ngs. 



POSITION UNCERTAIN. 



Orthonotella Miller and Faber (Crustacean?). 



Class AMPHINEURA. 



Order POLYPLACOPHORA. 



Family GRYPHOCHITONID^ Dall. 

 Priscochiton Dall. 



Class GASTROPODA. 



Order AsPiDOBRANCHiA. 



Family ACMEID/E Dall. 



Archinacella Ulrich and Scofield, Conchopeltis Walcott, Helcionopsis Ulri(;h and 

 Scofield, Hypseloconus Berkey, Metoptoma Phillips, Palaeacmsea Hall, Scenella 

 Billings. 



Family TRYBLIDIID^E Pilsbury. 



Tryblidium Lindstrom. 



Family CYRTOLITID^E Ulrich and Scofield. 

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



Family SINUITID^E Bassler. 

 Bucanella Meek, Sinuitos Koken. 



