352 MYID.E. 



impressions wide apart, the hinder elongate; pallial line 

 irregular, strongly marked, the posterior sinus very small. 



Syn. Glycimeris, Lam., not Klein or Schum. 



Ex. C. siliqua, Spengler, pi. 94, fig. 4. Shell, C. siliqua, 

 fig. 4, a, 4, b. 



Cyrtodaria siliqua is found in the littoral zone of 

 Northern and Arctic seas, living buried in the sand. In 

 general aspect the shell resembles that of some of the 

 Solens, being covered with a thick, horny epidermis, but the 

 siphons of the animal are not entirely retractile, and are 

 enclosed in a tough, coriaceous, wrinkled envelope, as in 

 Glycimeris and Panojxea. The palpi in Cyrtodaria are large 

 and sickle-shaped, the mantle is thickened at the margin, 

 and invested, like the siphons, with a wrinkled epidermis, the 

 pedal opening is very small and quite anterior, and the gills 

 are thick, plaited, and unequal, the outer one being the 

 shortest and rounded in front. In many respects the animal 

 resembles that of Mya, but the cartilage of the hinge is 

 external, and the hinge itself edentulous and simple. 



Species of Cyrtodaria. 

 Cuniingii, Dkr. siliqua, Spengl. 



Fam. MYIDiE. 



Body not symmetrical. Labial palpi small. Mantle 

 almost entirely closed except for the passage of a small foot ; 

 siphons invested with a coarse and wrinkled epidermis, 

 greatly prolonged and united almost to their extremities, the 

 orifices fringed ; gills two on each side, elongated, depen- 

 dent. Foot small. 



