208 CARDIUM. 



Orknies. Mr. Montagu has met with it on the coast 

 of South Devonshire, particularly on Dawlish Warren, 

 and at Tor-cross. 



Fig. 1. pi. 51. is the exotic variety of this species. 

 It is of a tawny colour, and more closely set with spines 

 and knobbs, than our shell. It inhabits the Indian 

 ocean, and is well figured by Chemnitz, vol. 6. pi. 15. 

 f. 157. 



THORNY COCKLE. 

 PI. 49. f. 1, 2. 



2. Cardium echinatura, T. testa subcordata, costis exaratis, linea ci- 



liata, aculeis inflexis plurimis. Linn. Syst. Nat. ed. 12. p. 1 122. 



Linn. Gmel. p. 3247. 

 Shell somewhat heart-shaped, ribs liueated down the middle, spines for 



the most part inflected. 

 Testa cordato-ovata, subeequilatera, costis confertis, linea exaratis, aculeis 



inflexis numerosis. Brug. Ency. Meth. Hist. Nat. 6. p. 217. 

 List. An. Aug. pi. 5. f. 33. Conch, pi. 324. f. 161. Bonan. 



Recr. 2. f. 90. Seba Mus. 3. pi. 86. f. 3. Murray in Amozn. Acad. 



pi. 2. f. 19. Muller Zool. Dan. p. 46. pi. 13. f. 12. and pi. 14. f. 



1—4. Da Costa, Brit. Conch, p. 176. pi. 14. f. 2. Chem. Conch. 



6. pi. 15. f. 158. Encyclop. Method, pi. 298. f. 3. Pult. in Hutch. 



Dorset, pi. 6. f. 2. Donov. Brit. Shells, pi. 107. f. 1. Mont. Test. 



Brit. p. 78. Linn. Trans. 8. p. 63. 



A smaller shell than the preceding, of a dull whitish, 

 or yellowish-brown colour, with nineteen longitudinal 

 ribs, set with white, enameled spines, some erect, and 

 others inflected ; intermediate furrows deep, and trans- 

 versely striated. The inside white, with flat ribs ; hinge 

 with four teeth in each valve, two approximate, and two 

 remote; each of the remote, or lateral teeth, in one 

 valve, have an interior depression, which receives the 



