162 MOLLUSC A. SOLENIDtE. Panop.ea. 



Chamce-pholas angusta, List. Conch, t. ccccxxvi. — Solen ininutus, Linn- 



Syst. 1115. — Mya arctica, Fab. Fauna Groen. 407 — Curious Muskle. 



Cordiner's lluins, Plate No. 24. f. A.— Solen niinutus, Mont. Test. Brit. 



53. t. i. f. 4 — Hiatella minuta, and H. oblonga, Ticrt. Biv. Brit. 24. t. ii. 



f. 12, 13 — Anatina arctica, ib. 49. t. iv. f. 7: 8. — E.oots offuci. 

 This species, when young, has the spinous ridges very distinct ; and, when 

 not imbedded in stone, it adheres by a byssus. When old, the spinous ridges 

 disappear, and then in size, and other circumstances, it so exactly resembles 

 the preceding, as to leave little room for suspecting a specific difference. The 

 Mytilus prcecisus of Montagu, (Test. Brit. 1G5. t. iv. f. 2.) seems to be a varie- 

 ty in which the anterior end is truncated, and very short, and the beaks ele- 

 vated ; while the M. jMcatus of the same author only differs in the beaks be- 

 ing small and slightly incurvated. 



EXTINCT SPECIES. 



1. H. sulcata. — Beak nearly terminal ; both extremities rounded ; shell 

 thin, concentrically sulcated, the ridges large retrally, formed by the union 

 of two or more ribs ; closely and obsoletely striated longitudinally, the 



striae consisting of minute tubercles Not uncommon in the Carlonifermis 



Limestone of the Forth Coal-Field. 



Gen. CXXXVIII. PANOPtE A.— SheU transverse, unequal- 

 ly open at the sides ; a single conic tooth in each valve, mth 

 an adjoining short compressed callus, to which an external 

 ligament is attached. 



575. P. Aldrovandi. — Truncated at both extremities, and 

 coarsely wrinkled transversely. 



Chama Glycimeris, List. Conch, t. ccccxiv — Mya Glycimeris, Don. Brit. 



Shells, t. cxlii P. Gly. Turt. Biv. Brit. 42.— English coast, rare. 



Length about 4 inches, breadth 8 ; coarse and thick ; a series of wrinkles 

 behind the teeth. One specimen from the Dogger-bank occurred to INIr Do- 

 novan, and a fragment of a valve found on, the beach at Teigumouth, b}' Dr 

 Turton, are the only British examples of this shell, which is sometimes found 

 on the coast of France and Spain. 



MYAD^. 



Gen. CXXXIX. MYA. — Equivalve, transverse, gaping; 

 hinge with a single projecting dilated tooth in the right 

 valve, for supporting the ligament, with a pit in the left. 



576. M. truncata. — Shell rounded anteally, abruptly trun- 

 cated retrally ; the ventral margin nearly straight. 



Concha laevis, List. An. Ang. 191. — Conch, t. ccccxxviii. — M. trun. Liniu 

 Syst. Nat. i. 1112. Penn. Brit Zool. iv. 78. t. xli.-f. 14. Mmt. TesU 

 Brit. 32. T^lrt. Biv. Brit. 31.— Common near low water-mark, lodged 

 in sand or gravel. 



