313 MYTILUS. 



u it seems to differ essentially from either the M. Cygneus or 

 M. anatinus, and is much less like either than those shells 

 are to each other." It is broader in proportion to the length, 

 more convex, and has the umbones smaller than M.Jiuvia- 

 tilis. 



dubius. 38. Shell transversely ovate and wrinkled, 

 rounded at both, and broader at the anterior 

 end ; umbones obsolete. 



Mytilus dubius. Gmelin, p. 3363. 



Mytilus plicatus. Solander's MSS. Portland Cat. p. 183. 



lot 3910. Callone's Cat. p. 59- No. 1080. 

 Mytilus, No. 56. Schroeter Einl. iii. p. 471. 

 Le Mutel. Adanson Senegal, p. 234. t. 17. f. 21. 



Inhabits rivers and lakes in Senegal. Adanson. China. Hum- 

 phreys. 



Adanson describes this species to be two inches long, nearly five 

 inches broad, and two inches high ; the anterior is consider- 

 ably broader than the posterior end, and both are rounded ; 

 the outer surface is tawny, and the inside very pearly and iri- 

 descent. I have little doubt that this is the M. plicatus of 

 Solander, and of this a specimen is thus described in Mr. 

 Humphreys's Catalogue of the Portland Cabinet, " a fresh- 

 water shell from China, each valve having a row of six pearls, 

 all furnished with stalks, explaining an artifice made use of 

 by the Chinese, in assisting nature in the formation of pearls, 

 by fastening knobbed wires on the inside of the shell while 

 the animal was living, which was afterwards replaced in the 

 river or other place it was originally in, and in process of 

 time, coated the wire* over with the pearly substance of its 

 shell." 



ruber. 39. Shell wrinkled, with the valves oblique 

 and dilated on the anterior side; cardinal 

 margin equalling the apex. 



Mytilus ruber. Linnaus Syst. Nat. p. 1158. Gmelin, 

 p. 3356. 



Inhabits the Southern Ocean. Linnceus. 



This shell is said to be minute and convex, with a very short 

 compressed tooth in the hinge. It is probably the young of 

 some other species, but Dr. Solander in his MSS. has refer- 

 red to the middle figure H of Gualter's tab. 91, and consider- 

 ed Myt. incurvatus of Pennant to be a variety. 



