192 MYTILID^. 



discrepans of IMoiitagu and Turton ; but in this lie is at variance 

 with the opinions and ligures of all other authors.* 



Modiolaria discors. 



Fig. 83. 



Shell sub-oval, broadest beliiml; beaks nearly terminal; hinder extremity- 

 somewhat lobed; surface divided into three compartments, of which the ante- 

 rior is marked by about ei-'ht, and the posterior by numerous radiating hues; 

 epidermis olivaceous. 



Mytilus diso-ppaiis, Moxtagu, Tost Brit. 160. — Dillwyn, Catal. i. 319. — Turton, 



Conch. Diet. 112; Brit. Fauii. 104. — Flkming, Brit. Aiiim. 413. 

 Mi/tihis discors, Liv. Syst. Nut. 12th cd. 1150. — Loven, Iiid. Moll. Scand. 33. — Ma- 



TON and Kackktt, Lin. Trans, viii. Ill, pi. 3, tiy. 9. — Hanley, Ipsa Lin. Conch. 



46. 

 Modio'a hrn'fjnla (vav.), Gray, Apjiendix to Parry's 2d Voyage, 24.5. 

 Modiola discri'iKins, Lam. An. sans Vert. 2d ed. vii. 23. — Turton, Brit. Biv. 202. — 



Forbes, Ma\. Moncns. 44. — Thorpe, Br. Mar. Conch. 108. — Gould, Inv. 120, fig. 



83. — Hanley, Recent Shells, i. 242. — Mighels, Shells of Maine, Journ. Bost. 



Soc. iv. 327.— Dk Kay, Nat. Hist. N. Y. 185. 

 Modiolaria discors, Loven, Ind. Moll. Scand. 33. 

 Crenella discors, Forbes and ILvnl. Br. Moll. ii. 105, pi. 45, figs. 5, 6; pi. 48, fig. 5. — 



Gray, Cat. Moll. 120. — Adams, Gen. ii. 514, pi. 121, fig. 3. 

 Mytilus discors, Stimpson, Inv. Gr. Manan, 21 ; Shells of New England, 12 (1851). 



Shell somewhat oval, rather oblique, highest about the middle, 

 rounded before, base slightly curved, hinge-margin straight and then 



curving obliquely downward ; beaks near the 

 ^^^^^ anterior end prominent, and rounded ; valves 



moderately convex ; surface coarsely marked 

 l)y the lines of growth, and divided into 

 three fan-shaped compartments, of which the 

 foremost one is marked l)y about eight small, 

 ji77,^oTr rounded, rib-like ridges, the spaces between 



them l)cing flat, the hinder one by numer- 

 ous similar ridges, and the central one is plain, or with very minute 

 radiating lines ; the limits between the posterior and middle com- 

 partments are designated by an elevated ridge passing from the 

 beaks, and here the basal mai'gin of the posterior compartments 

 projects abruptly beyond that of the middle one, so that the rounded 

 point of the shell forms a projecting lobe. Epidermis olive-green, 



* Dr. Gould appears to have changed his opinion in regard to the identity of Modiola 

 iicxii with the European M. nigra, as in h's MSS. he places the former in the synonymy 

 of the latter. Fig. 487 represents the typical nexa, fig. 488 the tiiyra from north shore 

 fisheries. — W. G. B. 



