170 



it has only eight, or nine, clearly defined ribs, on the fide 

 next to the beak; whereas the other has double that num- 

 ber; which chara61er is invariable: and this is never 

 otherwife than of an uniform colour, without fpots or 

 markings of any kind. No author feems to have dillin- 

 guiflied this fpecies, although fo eflentially different from 

 the M. difcors. ^ 



We found this fliell alive on the fhore between South- 

 ampton and the mouth of the Itchin, in vafl: abundance; 

 and not uncommon at Ilfracomb in DevovJIiire, in the 

 holes or crevices of the rocks, and among various marine 

 plants, near high-water mark; have alfo received it from 

 the fouth coafl; o{ Wales. 



This is always found detached, and never buried in ani- 

 mal or vegetable fubftances, like the difcors; though it 

 frequently adheres flightly by its hyjfiis. 



12. 

 Cygxecs. Mytilus Cygncus. Lin. Syfi. p. 1158. — GmeJ. Syft. p. 3355. 



Lifter Conch, t. 156. f. 11. 

 Chem. Conch, viii. t. S6. f. 762, 

 Br. Zool. t. 67. f. IS.—Ba Cofla p. 214. 

 PuJt. Cat. Dorfet. p. 3S.—Gua!t. t. 7. F. 

 Don. Br. Shells, ii. t. 55. 

 Turt. Lin. iv. p. 293. 

 Muller p. 208. No. 394. 

 Si-hroet Fluffconch. t. 3. f. 1 . 



M. with 



