PINNA. 255 



less ; ligament linear, internal. Pallial impression entire, 

 muscular sears very unequal. 



Animal triangular, mantle freely open, no siphons ; 

 mantle-margins with cirrhated edges ; mouth with foli- 

 aceous lips and short palps ; anus furnished with a long 

 lingulate valve ; foot small, with a byssal groove ; adductor 

 muscles very unequal. 



This genus is an ancient one ; species of it presenting 

 marked resemblance to existing forms are present in oolitic- 

 strata. The number of living species is not great, but they 

 are widely distributed, and many of them remarkable for 

 their size. Our native Pinna is the largest bivalve in- 

 habiting the British seas. The Pinna are mostly sub- 

 littoral, but are capable of considerable ranges in depth. 

 They live in sand and mud, their gaping extremity up- 

 wards and their beaks plunged deep in the ground. Their 

 byssus is strong and silky, and in Sicily is sometimes made 

 into gloves or stockings, more for curiosity than use. A 

 little crab is often found within the shell when the true 

 inhabitant is alive, and many fables have been narrated of 

 their friendship. 



P. pectinata, Linnaeus. 



Plate XLIII. fig. 1, 2, and Plate LIU. fig. 8. 



Pinna pectinata, Linn. Syst. Nat. ed. 12, p. 1160. — Pulteney, Hutchins, Hist. 

 Dorset, p. 39. — Mont. Test. Brit. p. 178. — Maton and 

 Rack, Trans. Linn. Soc. p. 113. — Rackett, Dorset Catalog. 

 p. 41, pi. 3, f. 3. — Turt. Conch. Diction, p. 148, f. 1 1 ; Dithyra 

 Brit. p. 223, pi. 19, f. 1.— Fleming, Brit. Animals, p. 406. 

 — Lam. Anim. s. Vert. (ed. Desh.) vol. vii. p. 64 (partly). — 

 Dillw. Recent Shells, vol. i. p. 325. — Mawe, Linn. Conchol. 

 pi. 17, f. 1.— Hanl. Recent Shells, vol. i. p. 253. 

 „ fragilis, Penn, Brit. Zool. ed. 4, vol. iv. p. 14, pi. 69, f. 80. — Turt. 

 Dithyra Brit. p. 222, pi. 20, f. 2. — Fleming, Brit. Anim. p. 



