192 MYTILID^. 



discrepans of Montagu and Turton ; but in this he is at variance 

 with the opinions and figures of all other authors.* 



Modiolaria discors. 



Fig. 83. 



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

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

 I'ior is marked by about eight, and the posterior by numerous radiating lines; 

 epidermis olivaceous. 



Mytilus disrrrpans, MoxTAGU, Test Brit. 160. — Dillwyn, Catal. i. 319. — Turtox, 



Conch. Diet. 112; Brit. Faun. 164. — Fleming, Brit. Aiiim. 413. 

 Mytilus discors, lAy. Syst. Nat. 12th ed. 1159. — Loven, Inch Moll. Scand. .33. —Ma- 



TON and Rackett, Lin. Trans, viii. Ill, pi. 3, fig. 9. — Hanley, Ipsa Lin. Conch. 



46. 

 Modio'a hpvi(/ata (var.), Gray, Appendix to Parry's 2d Voyage, 24.5. 

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



Forbes, Mai. Monens. 44. — Thorpe, Br. Mar. Conch. 108. — Gould, Inv. 129, fig. 



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



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

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

 Crenclla discors, Forbes and Hanl. Br. Moll. ii. 195, 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 oldique, 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 

 by the lines of growth, and divided into 

 three fan-shaped compartments, of which the 

 foremost one is marked by about eight small, 

 rounded, rib-like ridges, the spaces between 

 them being 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 tmd middle com- 

 partments are designated by an elevated ridge passing from the 

 beaks, and here the basal margin 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 

 vexa with the European M. nir/rn, as in h's MSS. he places the former in the synonymy 

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

 fi>;herics. — W. G. B. 



