360 ANATINID.E. 



Genus anatina ; Lamarck. 



Siphons long, united, covered with a rugose epidermis. 



Shell thin, translucent, oolong, ventricose, sub -equi valve, 

 gaping and attenuated at the hinder side ; beaks fissured, 

 directed backwards, supported internally by an oblique plate. 

 Hinge composed of a spoon-shaped cartilage-process in 

 each valve, projecting internally, furnished in front with a 

 transverse ossicle. Pallial line with a wide, shallow sinus. 



Sy?i. Auriscalpium, Megerle. Butor, Gistel. Cyatho- 

 donta, Conrad. 



Ex. A. subrostrata, Lamarck, pi. 96, fig. 1. Shell, A. 

 subrostrata, fig. 1, a, 1, b. 



In Anatina the pedal opening is small and quite an- 

 terior ; the palpi are very long, narrow, free, and striated 

 inside ; the gills are long and narrow and not continued 

 into the branchial siphon, and the dorsal border is free and 

 nearly as wide as the gill; the siphons are united, thick, 

 and covered with a rugose epidermis ; and the foot is very 

 small and compressed. The shells are thin and semitrans- 

 parent, and the surface of the valves is hispid or rough with 

 calcareous points ; the ossicle, or peculiar shelly plate cover- 

 ing the cartilage, is linear. The species are principally from 

 tropical seas, being found in India, the Philippines, New 

 Zealand, and South America. The extinct genera Cer- 

 comya and Rhynchomya, of Agassiz, are founded on fossil 

 shells closely resembling those of Anatina. 



Species of Anatina. 



alta, C. B. Adams. elegans, Phil. 



anserifera, Spengl. globulosa, Lain. 



