LAMELLIBRANCHIATA. 485 
Classification of paleozoic Lamellibranchiata. ] 
CLASSIFICATION OF PALEOZOIC LAMELLIBRANCHIATA. 
Subkingdom MOLLUSCA. 
Class LAMELLIBRANCHIATA, Blainville. 
Order ASIPHONIDA, Woodward. 
Mantle lobes separate, siphons wanting. Pallial line without sinus. 
Suborder MONOMYARIA. 
A single adductor muscle, the anterior one wanting. 
Family PHCTHNIDAS, Lamarck. 
GENERA: Aviculopecten, McCoy; Crenipecten, Hall; Huchondria, Meek; Lyriopecten, Halil; Pernopecten, 
Winchell; Pterinopecten, Hall; Streblopteria, McCoy. 
Suborder HETHROMY ARIA. 
Anterior adductor muscle very small, the posterior one large. 
Family AVICULIDA, dOrbigny. 
GENERA: Actinopteria, Hall; Bakevellia, King; Ectenodesma, Hall; Glyptodesma, Hall; Liopteria, Hall; 
Leptodesma, Hall; Limoptera, Hall; Monoptera, Meek and Worthen; Monotis, Bronn; 
? Paleopinna, Hall; Posidonomya, Bronn; Pseudomonotis, Beyrich; Pterinea, Goldfuss ( Ver- 
tumia, Hall); Pteronitella, Billings; Pteronites, McCoy; ? Ptychopteria, Hall. 
‘ Family PINNIDAS, Gray. 
GENERA: Aviculopinna, Meek; Pinna, Linne. 
Family AMBONYCHIIDA, Miller. 
GENERA: Allonychia, Ulrich; Ambonychia, Hall (restricted); Amphicelia, Hall; Anomalodonta, Miller; 
Anoptera, Ulrich; Byssonychia, Ulrich; Byssopteria, Hall; Clionychia, Ulrich; Hctenoptera, 
Ulrich; Hridonychia, Ulrich; Mytilarea, Hall; Paleocardia, Hall; Plethomytilus, Hall. 
Psilonychia, Ulrich. = 
Family CHAVNOCARDIID AQ, Miller. 
GENERA: Chenocardia, Meek and Worthen; Megambonia, Hall. 
Family MYTILIDAY, Lamarck. 
GENERA: ? Anthracomya, Salter; ? Anthracoptera, Salter; Gosselettia, Barrois; Lithodomus, Cuvier (Litho- 
phaga, Bolton); Modiella, Hall; Modiola, Lamarck; Myalina, Koninck; Mytilops, Hall; 
? Spathella, Hall. 
Family MODIOLOPSIDAS, Ulrich. 
GENERA: Actinomya, Ulrich; ? Aristerella, Ulrich; Colpomya, Ulrich; ? Cymatonota, Ulrich; ? Cypricardella, 
= Hall; ? Endodesma, Ulrich; EHurymya, Ulrich; Goniophora, Phillips; Modiolodon, Ulrich; 
Modiolopsis, Hall; Modiomorpha, Hall; Orthodesma, Hall and Whitfield; ? Prolobella, Ulrich; 
? Psiloconcha, Ulrich; ? Pyanomya, Miller. 
