106 MOLLUSCA. 



tooth en chevron ; but the lateral plates are wanting ; the gap of the 

 valves is very wide, particularly at the posterior extremity, through 

 which passes the thick, double, fleshy, respiratory and anal tube, a 

 disposition which attaches them to this family. The foot, which 

 issues at the opposite end, is small and compressed. 



Some of them are found in the sand at the mouths of rivers in 

 France *. In the 



MYA, Lam., 



Or the Mya properly so called, one valve is furnished with a plate 

 which projects into the other, and this latter with a cavity. The liga- 

 ment stretches from this cavity to that plate. 



Some species are found in the sand along the coast of 

 France f. 



ANATINA, Lam. 



The Anatinse of Lamarck should be approximated to the preceding 

 Mya\ Each of their valves has a small projecting plate inside with 

 the ligament extending from one to the other. 



One oblong and excessively thin species is known, the valves 

 of which are supported by an internal ridge J ; and another of a 

 squarer form without the ridge . In the 



SOLEMYA, Lam. 



The ligament is seen on the outside of the shell, part of it remaining 

 attached to a horizontal internal cuilleron on each valve. There is 

 no other cardinal tooth, and a thick epidermis projects beyond the 

 edges of the shell. 



One species, the Tellina togata, Poll, II, xv, 20, is found in the 

 Mediterranean ||. 



GLYCYMERIS, Lam. CYRTODABIA, Daud. 



Neither teeth, plates, nor cavities on the hinge, but a simple callous 

 enlargement, behind which is an external ligament. The animal re- 

 sembles that of the Myae. 



The most common species Mya siliqua > L.; Chcmn. XI, 193, 

 f. 194, is from the Arctic Ocean. 



* Mactra lutraria, List., 415, 259 ; Chemn., VI, xxiv, 240, 241 ; Mya oblonga, 

 Id., Ib., ii, 12 ; Acosta, Brit. Conch., XVII, 4 ; Gualt., 90, A, fig. min. 



f Mya truncata, L., Chemn., VI, i, 1, 2; M. arenaria, Ib., 3, 4. 



J Solen anatinus, Chemn., VI, vi, 46 48. 



Encyc., 230, 6, under the name of Corbitlc ; An. hispidula, Cuv., An. sans vert., 

 Egyp. Coq. pi. vii. f. 8. I suspect that the Rui'icoL.E of F. de Bcllcvue (Voy. 

 Roissy, VI, 440) must appfoach this subgenus. They live in the interior of stones, 

 like the Petricoltf, Phulades, &c. 



|| New-Holland furnishes a second species, the Sol. auslrulis, Lam. 



