M Y T 1 L L S 



Species V.i. (Mus. Cuming.) 



MvTii.us Amkuican'us. Mi/f. ledd Irigono-ovala, k'uni, 

 convexd, conceiitrice striata; olivaced, subserieed. 



The American Mytilus. SIicll triangularly ovate, 

 tliin, convex, concealrically striated ; olive, somewhat 

 silky. 



Drcmma Amtrkaua, Kecluz, WS. in Mus. Cuming. 



Hah. Florida. 



A delicate silky olive shell, of thiu substaiur, rather 



convex. 



Species W. (Mus. Cuming.) 

 MvTii.i's Sallei. Mijt. testa Ingouo-flabeUatd, ciirmld, 



postice impressa, umbonibus acute roslraiis ; sordide 



fuscescente, strujis nigricantiJbus remotk concentrice 



j)idd. 

 Salle's Mytilus. Shell triangularly fan-shaped, curved, 



posteriorly impressed, umboes sharply beaked ; pale 



dirty-brown, concentrically painted with distant 



blackish streaks. 

 Dreissetm Sallei, Recluz, Revne de Zool. 1819, p. 6;); 



Journ. de Conch, vol. iii. p. 2.55. pi. 10. f. 9. 

 JIab. Central America. 



Of a ( 

 neath thi 

 beaked. 



I fan-shape, impressly nipped be- 

 uianner to render them sliarply 



Species 45. (Mus. Cuming.) 



Species -K;. (Mn<. Cuming.) 



Mytilus tknebuosi.-s. Mt/t. tedd elongald, postice valde 

 tjibbosd, latissimd, plano-impressd, ad amjulum acuta ; 

 cmriduHcente-ulbd, nigra concentrice strigatd, epider- 

 mide Jibrosd olivaceo-nigricante indutd. 



The dark Mytilus. Shell elongated, posteriorly very 

 gibbous, very broad, flatly impressed, sharp at the 

 angle ; bluish-white, eoucentrically streaked with 

 black, covered with an olive-black tibrous epidermis. 



Dreisseua Cumingiana, llechiz, IMS. in Mus. Cuming. 



Ilab. Mississippi. 



Of elongated form, remarkably gibbuus, aiid broadly 



flatly impressed on the posterior side. 



Species 47. (Mus. Cuming.) 



MYTlHiS AfeicanUS. Myl. testd sitbeloiigafd, postice vix 

 imprcssd ; sordide fused, epidermide Jibrosd concentrice 

 indutd. 



TjiB African Mytilus. Shell rather elongated, poste- 

 riorly scarcely im])ressed ; dirty-browu, concentrically 

 invested with a fibrous epidermis. 



Dreissena ///"Wfiowa, Vanbenedeu, Ann. de Sci. Nat. 1S35. 



Hub. Senegal. 



The peculiarity of this species consists in its simple 



convexly elongated form, the posterior side showing 



scarcely any of the depression commonly typical of the 



Dreissena group. 



Mytilus Rossmassleri. Myt. testd trigono-Jlabellatd, 



subcurvatd, solidiasctdd, postice late impressa, gibiosd, \ 



albidd, epidermide tenui fiiscesceide concentrice Jtoc- 



catd. j 



Bossmassler's Mytilus. Shell triangularly fan-shaped, I 



somewhat curved, rather solid, posteriorly broadly 



impressed, gibbous; whitish, concentrically flaked [ 



with a thin light-brown epidermis. j 



Dreissena Eossmassteri, Dunker, MS. in ,Mus. Cuming. ' 



Hab. United States. ,' 



Chiefly distinguished by its broadly impressed gibbons I 

 growth on the posterior side, and characteristic epidermis, 

 which consists onlv of thin concentric flakes. 



Species 48. (Mus. Cuming.) 



Mytilus Domingensis. Mgt. testd elongatd, subcurvatd, 

 versus umboues attenuatd el rostrald, postice subim- 

 pressd ; purpvreo-fuscd, subrude concentrice striata. 



The Domingo Mytilus. Shell elongated, slightly 

 curved, attenuated and beaked towards the luuboes, 

 faintly impressed posteriorly ; purple-brown, some- 

 what rudely concentrically striated. 



Drdssena Donungensis, Recluz, Journ. de Conch, vol. iii. 

 p. 255. pi. 10. f. 8. 



J/ab. St. Domingo ; Salle. 



Characterized by a ] 

 in the direction of the 



nttenuatelv beaked contour 



