110 CONCHIFERA. DIMYAIEA. 



Gen. 48. ANATINA, Lam. Mya, Solen, Lin. 

 Shell transverse, subequivalve, gaping at both sides, or at one 

 only ; one broad primary spoon-shaped tooth, projecting in- 

 teriorly in each valve ; a lateral plate running obliquely un- 

 der the primary teeth in the greater part. 



The shells of this genus are distinguished from the Myae by their spoon-shaped 

 tooth in each valve, while the latter have only one. The ligament is interior, and 

 attached in the hollow of the tooth. 



A. truncata, Lam. Shell ovate, slender, transversely striated, sub- 

 truncated before, rough, with prominent points. Inhabits Eu- 

 ropean seas. Lam. v. 463. 



A. globulosa, Lam. (Mya anatina, Gmel.) Shell subglobose, with 

 decussated striae, white, pellucid ; anterior margin slightly gap- 

 ing. 1 inch long. Coasts of Africa. Chem. vi. pi. 2, fig. 13, 16. 



A. declims, Lam. (Mya, Pen.) Shell ovate, obliquely angulated, 

 and subtruncated at the anterior end ; rough to the touch, and 

 marked with concentric striae. 1^ inch long, and 2 inches broad. 

 Inhabits British coasts Wood's Conch, pi. 18, fig. 2, 3. 



Gen. 49. MYA, Lam. Lin. 



Shell transverse, gaping at both ends ; left valve with a large, 

 compressed, rounded tooth, projecting almost vertically, and 

 a hollow in the other valve ; ligament interior. 



The animals of this genus have the mantle united before, and at one extremity a 

 short, compressed, thick foot ; at the other a large tube, which contains two smaller, 

 the one for the entrance of water, the other the anal orifice. The Myae are marine, 

 transverse, inequilateral shells, and open more or less at both extremities like the 

 Solenes. They have but one tooth at the hinge in the left valve, and this tooth is 

 large, and hollowed to receive the ligament. It shuts the cavity in the other valve 

 when the shell is closed. The ligament is interior, attached in one part to the pro- 

 jecting tooth, and in the other to the hollow of the right valve. The Myae burrow 

 in the sand, and project a long tube to the surface. 



M. truncata, Lin. Shell ovate, truncated behind ; hinge with a 

 projecting and very obtuse tooth ; colour whitish ; epidermis yel- 

 lowish, wrinkled. 1^ to 2J inches long, and 2^ to 3^ broad. 

 Inhabits European seas. B. Wood's Conch, pi. 17, fig. 1, 2. 



M. arenaria, Lin. Shell ovate, rounded behind ; hinge with a 

 rounded tooth, projecting forwards, and a smaller one by its side; 

 colour whitish, with a wrinkled brown or chestnut epidermis, and 

 glossy white within. 2 inches long, and 3^ broad. Inhabits Eu- 

 ropean seas. B. Wood's Conch, pi. 17, fig. 3. 

 Both these species are found plentifully on the coast of the Frith of Forth, near 



Edinburgh. A hollow depression in the sludge marks the place where they are 



found. 



FAMILY II. SOLENIDES. 



Shell elongated transversely, without accessory pieces, and gaping 

 only at the lateral extremities ; ligament exterior. 



The shells of this family are bivalve, equivalve, often much elongated transversely. 

 The primary teeth are very variable ; for some have only one in each valve, others 

 one in one valve and two in the other ; and others two in one and three in the other 



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