422 MOLLUSCA. CARDIADiE. Cabdium. 



435. C. elongatum. — Shell, rounded, compressed, with about 



25 flattened prickly ribs. 



Mont. Test. Brit. 82. Turt. Biv. Brit. 185. t. xiii. f. 8 — Devonshire and 

 Zetland. 



Shell about a quarter of an inch in diameter : produced, and a little angu- 

 lar at the cartilage side 5 the spines are broad and thin, corresponding with 

 the size of the ribs. 



436. C. exiguum. — Shell sub triangular, retrally truncate, 

 with from 20 to 22 tubercled ribs. 



Pectunculus exiguus. List. Conch, t. cccxvii— Cardium subcordatum. 



Walker's Test. Min. 23. t. cxi. f. 83 — C. pygmseum, Don. Brit. Shells, 



t. xxxii. f. 3 — C. ex. Mont. Test. Brit. 82. Turt. Biv. Brit. 187 — 



Various parts of the coast from Devon to Zetland. 



About half an inch in diameter, transversely striated ; the ribs rounded 



with a mesial ridge, the tubercles are short, and somewhat arched. 



** Rths armed zoith transverse scales. 



437. C. edule. — Common Cockle. — Shell somewhat globular, 

 with about 26 ribs, rounded and interruptedly sulcated trans- 

 versely. 



Pectunculus vulgaris. List. An. Ang. 189. Conch, t. cccxxxiv Car- 

 dium edule, Linn. Syst. i. 1124. Pejin. Brit. Zool. iv. 91. t. 1. f. 41. 

 Mont. Test. Brit. t. 7G. Don. Brit. Shells, t. cxxiv. f 1, 2. Turt. 



Biv. Brit. 188 Common in sand, near low water-mark. 



Diameter about 2 inches, yellowish-white ; nearly equilateral, or produced 

 posteriorly ; and more or less rugged by the layers of growth. — Cockles form 

 a very palatable food, either raw or boiled, and are considered in highest 

 season in the spring months. 



438. C. Jasciatum. — Shell slightly compressed with about 



26 ribs ; those in the middle smooth, the extreme ones scaly. 



Mont. Test. Brit. Sup. 30. t. xxvii. £ C. Turt. Biv. Brit. 189 — Various 

 parts of the coast. 

 Diameter |ths of an inch ; nearly equilateral, whitish, with irregular ru- 

 fous bands ; the ribs are a little flattened ; the thin transverse scales some- 

 times extend in front along the margin. 



*** Ribs unarmed. 



439. C. medium. — Shell subtriangular, truncated retrally, 

 with a prominent hne of junction ; ribs about 36. 



Pectunculus subrufus, Z-wA Conch, t. cccxvi — C. med. Linru Syst. i. 1122. 

 Don. Brit. Shells, t. xxxii. f, 1. Mont. Test. Brit. 83. Turt. Biv. 



Brit. 189 English coast, rare. 



Length upwards of an inch ; yellowish-white, with brown blotches; ribs 

 flattened, furrows crossed by fine striie. This species is common to the Me- 

 diterranean and West Indies. The specimen figured by Donovan from Har- 

 tlepool, and another, referred to by Dr Turton, as taken alive at Torquay, 

 are the only instances as yet recorded of its occurrence in our seas. 



