m 
MOLLUSCA. SOLENID/E. 
Panop^a- 
Chamse-pholas angusta, List. Conch, t. ccccxxvi — Solen minutus, Linn^ 
Syst. 1115. — Mya arctica, Fab. Fauna Groen. 407- — Curious Muskle. 
CordineFsl^mn% Plate No. 24. f. A.— Solen minutus, Mont. Test. Brit. 
53. t. i. f. 4 — Hiatella minuta, and H. oblonga, Turt. Biv. Brit. 24. t. ii. 
f. 12, 13 — Anatina arctica, ib. 49. t. iv. f. 7, 8. — Boots of fuci. 
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 prcBcisus of Montagu, (Test. Brit. 165. 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. plicatus 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 Carboniferous 
Limestone of the Forth Coal-Field. 
Gen. CXXXVIII. PANOP^EA. — Shell transverse, unequal- 
ly open at the sides ; a single conic tooth in each valve, with 
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 Mr Do- 
novan, and a fragment of a valve found on the beach at Teignmouth, by 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. Linn. 
Syst. Nat. i. 1112. Penn. Brit. Zool. iv. 78. t. xli. f 14. Mont. Test. 
Brit. 32. Turt. Biv. Brit. 31. — Common near low water-mark, lodged 
in sand or gravel. 
