SCROBICULARIA. 409 



In this genus the orifices of the siphonal tuhes are plain, 

 the mantle margin is denticulated, and the foot is large and 

 compressed. The animals usually live, buried vertically 

 five or six inches deep, in the mud of tidal estuaries ; the 

 siphons can be extended five or six times the length of the 

 shell. The species are found in Norway, Britain, the 

 Mediterranean, Senegal, India, China, and the Philippines. 



Species of Scrobicularia. 



borealis, Pfeiff. piperita, Gmel. 



Cottardi, Payr. Sicula, Sow. 



Sub-gen. capsa, Bosc. 



Shell ovate or sub-triangular, posterior side sbort, flexuous. 

 Hinge with the cardinal teeth small and laminar ; lateral teeth 

 none. 



alta, Conr. inflata, Schum. 



angulata, Chem. lacunosa, Chem. 



biangulata, Cpr. obesa, Desh. 



Chemnitzii, Desh. plebeia, Hanley. 



contorta, Desh. producta, Cpr. 



Deshayesii, H. and A.Adams spectabilis, Hanley. 



(spectabilis, Desh.). trigonalis, Adams and Reeve. 



ephippium, Spenrjl. turgida, Desh. 



Sub-gen. iacea, H. and A. Adams. 



Shell sub-trigonal, surface of the valves divaricately sulcate, 

 posterior flexure strong. 



Seychellarum, A. Adams. 



