136 MYTILIDJE. 



bivalve. Mr. Bean kindly sent me a specimen of the 

 latter, and I described it in the ' Annals and Magazine 

 of Natural History' for January 1859 (p. 40) under the 

 name of Modiola cuprea. I subjoin the description : 



" Testa ovato-trapezoidea, gibbosa, solidula, nitida, epider- 

 mide prismatica, fulva (antice flava), pilosa vestita, subtus 

 albida, rugis concentricis raris irregulariter notata; angulo 

 transversali ex apicibus ad latus posticum oblique decurrente ; 

 timbonibus obtusis ; lateribus, dorsali rectiusculo elevatiore 

 postice rotundato, antico abrupte truncate, ventrali convexo 

 subsinuato antice declivi, posteriore quadrate ; marginibus in- 

 tegris ; bysso ex filis perpaucis curtis crassulis composito ; 

 long. , lat. ! unc." 



But this description is incomplete, inasmuch as 

 no mention is made of the internal structure of the 

 hinge. Having succeeded in opening the shell, after 

 steeping it for a long time in water, I am now enabled 

 to supply this deficiency ; and the result has compen- 

 sated for the care and patience bestowed on the opera- 

 tion. Each valve has on the anterior side of the beak 

 four small but prominent tubercular teeth, and on the 

 posterior side the same number of angular teeth, which 

 are set obliquely and resemble in shape those of Nucula 

 or Leda. The hinge-line is microscopically but indis- 

 tinctly notched, as in Crenella and some species of Area. 

 I do not know if this peculiar arrangement of tuber- 

 cular teeth on one side and of lamellar teeth on the 

 other side of the hinge has any parallel in bivalve 

 shells, unless it be the genus Nuculocardia of D'Orbigny. 

 The little shell in question is evidently littoral, judging 

 from the habits of the other species which were found 

 with it in the bird's stomach. From what coast, or 

 from what part of the northern hemisphere, it was 

 brought to our shores, it is almost impossible to con- 

 jecture. The animal was preserved in my specimen, 



