MYTILUS. MUSSEL. 109 



color, more strongly striate transversely, and covered with 

 a black-brown skin which folds into raised undulations ra- 

 diating from the beak to the margin. 



A specimen of this extremely rare shell was dredged up 

 by Mr. Prideaux, in Plymouth-sound, among some coral- 

 lines. 



3. Mytilus Crista Galli. Cockscomb Mussel. 



Bart>ut,pl.U.f. 1,2. 



Shell compressed, rugged, varying in shape, armed with 

 flat concave spines, and striate with raised dots, so as to 

 be transversely rugged and strongly plaited longitudinally ; 

 the margin undulately plaited, with the convexities of one 

 valve shutting into the concavities of the other : color fer- 

 ruginous or dull purple, opake ; inside smooth, horn-eolor : 

 lips both rough : hinge simple, linear, without teeth : 

 length about two inches ; breadth two and a quarter. 



On the bottoms of ships, v. v. 



4. Mytilus edulis. Common Mussel. 



Lister, pi. 362. f. 200 Pennant, pi. 66, f. 2 Da Costa, 

 pi. 15. f. 5, left hand fig. Linn. Trans, vi. pi. 18. f. 13, 

 14 Donovan, pi. 128 Dorset Cat. pi. 12. f. 5, left hand fig. 



Shell oblong, very convex, somewhat falcate or incurved 

 at the thicker or posterior margin, produced into a small 

 angle at the anterior side, and rounded at the front margin, 

 nearly smooth, covered with a dark and rather polished 

 skin, under which it is rich blue or radiate with blue and 

 white : beaks pointed, close together, with the appearance 

 of a prominent ridge on each side the margin down the; 

 posterior slope ; inside whitish with a blue margin, and 

 under the beak are several small tooth-like crenulations on 

 the margin : length three inches ; breadth one and a. half. 



Common, in vast beds. v. v f 



5. Mytilus incurvatus. Iiunirvid Mussel, 



Lister, pi. 362. f. 201, 202 Punwut, pi. 67. f. 1 

 limn. Trans, viii. pi. 3. f. 7- 



Shell oblong-oval, convex, opake, nearly smooth, of an 

 vmpolished greyish-blue color growing darker towards the 

 tides and front margin, much incurved cm the posterior 



