194 



PROCEEDINGS OP THE ACADEMY OP 



** With a single accessory valve. 



Dorsal valve lanceolate ; umbonal processes reflexed, 

 closely applied. Shell oblong-ovate Genus Barnea, Leach. 



Dorsal valve ovate-cuneiform; umbonal processes re- 

 flexed, cellular beneath. Shell oblong-ovate Genus Monothyra, Tryon. 



Dorsal valve small, transverse, posterior, under a cori- 

 aceous epidermis. Hinge plates produced and reflexed. 

 Shell ovate Genus Navea, Gray. 



***Destitute of accessory valves. 

 Beaks protected by a membrane. Valves ovate. ..Genus Zirph^ea, Leach. 



Subfamily JOUANNETLNLE. 



Anterior ventral gap closed in the adult by a callous plate. 



* With three dorsal accessory valves. 

 Anterior dorsal plates two, placed side by side, 

 posterior to which is a central plate, directly over the 

 umbones. Base of the siphons protected by reflected 

 appendages Genus Penitella, Valenciennes. 



** With two dorsal accessory valves. 



Dorsal valves small. The base of the siphons pro- 

 tected in the adult by a subtestaceous cup-shaped 

 appendage, which is absent in young individuals. 

 Valves ovate Genus Pholadidea, Turton. 



Surface impressed by two oblique sulci, extending 

 from the beaks to the margins. Shell ovate-oblong. 

 Valves equal Genus Parapholap, Conrad. 



*** With a single accessory valve. 



Shell globose, hinge plates not reflexed ; inequivalve, 

 the left valve overlapping the right Genus Jouannetia, Desmoulins. 



Shell ovate-oblong, accessory valve lanceolate or 

 peltate. Equivalve ; the surface impressed by one or 

 more furrows Genus Martesia, Leach. 



Index to the species of Pholadid;e. 



Anchomasa Pennantiana, Leach = Bar- 

 nea parva, Penn. 



Barnea Australasia, Gray. 



Baked, Desh.= B. Burmanica ? 



Burmanica, Philippi. 



Candida, Linn. 



Erythraea, Gray. 



frayilis, Sowb. = Manillensis, 



Philippi. 

 lanceolata, D'Orb. 

 Manillensis, Philippi. 

 parva, Pennant, 

 similis, Gray, 

 subtruncata, Sowb. 



Cadmusia Solanderiana, Leach = Phola- 

 didea papyracea, Soland. 



Dactylina Campechensis, Gmel. 



" " Gray,=D. Chi- 



loensis (part.) 



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Dactylina candeana, D'Orb. = D. Cam- 

 pechensis. 

 Chiloensis, King, 

 dactylus, Linn. 

 orientalis, Gmel. = Monothyra 

 orientalis, Gm. 

 Jouannetia Cumingii, Sowb. 



" Darwinii, Sowb.= Penitella 



penita. 

 globosa, Quoy. 

 globulosa, Quoy=J. globosa. 



(i 

 a 



u 

 1< 



pectinata, Conrad. 



pulcherrima, Sowb.= J. pec- 

 tinata. 



Martesia acuminata, Sowb. = M. calva. 

 aperta, Sowb. 

 Australis, Gray, 

 branchiata, Gould. 

 Cali/ornica, Conr. = Parapho- 

 las California. 



[April, 





