186 mytilidj:. 



Modiola modiolus. 



Shell oblong-ovate, gradually widening from before backwards ; hinge-margin 

 ascending, straight for about half the length of the shell; beaks tumid, obtusely 

 angular ; epidermis dark chestnut-color. 



Mjjtilus mod/olHS,!,!^!. Syst. Nat. 1158. — Pexn'.\nt, Brit. Zool. iv. 239, t 69. — MoN- 

 T.-iGU, Test. Brit. 163. — Ciiemn. Conch, viii. 178, t. 85, fig. 759. — Kxorr, Vergn. 

 iv. t. 15, fig. 3. — Lister, Conch, t. 1057, fig. 5. — Dillwyn, Catal. i. 314. — Wood, 

 Index, pi. 1-2, fig. 31; Lin. Trans, viii. 107. — Donovan, Brit. Shells, pi. 23.— 

 MiJLLER, Zool. Dan. ii. t. 53. -De Kay, N. Y. Moll. 185, pi. 24, fig. 257. 



Modiola modiolus, Tcrton, Brit. Biv. 199, pi. 15, fig. 3 (young); Conch. Diet. 111. — 

 Gould, Inv. 123. 



Mylilm Papuanus, Desiiayes, Encyc. Meth. Vers, iii. 564, pi. 219, fig. 1. 



Modiola Papuana, Lam. An. sans Vert. vii. 17. — Blainv. Malacol. pi. 64, fig. 3. — Say, 

 Am. Conch, pi. 45. 



Modiola vulgaris, Fleming, Brit. Anim. 412. 



Mytihis barbatus, Lin. Syst. Nat. 1156. — Donovan, Brit. Shells, pi. 70. — Montagu, 

 Test. Brit. 161. —Pennant, Brit. Zool. iv. 238, pi. 67, fig. 2. 



Mi/tilus umbilicatus, Donovan, Brit. Shells, fig. 40. 



Shell large, thick, coarse and solid, ovate-oblong; beaks placed 

 at one side, points inclined outwards, and projecting nearly as far 



M. modiolus. 



as the anterior extremity, which is very short and narrow ; the up- 

 per edge is ascending, and straight about one half tlie length of the 

 shell, when it curves gently downwards to the posterior extremity, 

 whicli is obtusely rounded; the basal margin is somewhat arclied up- 

 wards, and at the arclied portion the shell is gaping for the passage 

 of the byssns. From the beaks a very convex, broad ridge runs di- 

 agonally across the shell ; above this the shell is compressed, and 

 along its lower and anterior side is a broad depression or constric- 

 tion, terminating at the lower margin where the shell gapes. Sur- 

 face roughly marked by the lines of growth, and by a few faint, ra- 



