BIVALVIA. G7 



7. MODIOLA PLABELLULA, S. Wood. Tab. X1J1, fig. !), a — C. 



Spec. Char. JI. testa tenui, elongatd, irregulariter trapeziformi ; pedi-regione parody 

 brevi; siphoni-regione elongatd ct /allure ; radial o-coslalatd, costulis magnis, depressis, ali- 

 quando dichotomis ; margine venfrali subsinuato. 



Shell thin, elongate, irregularly trapeziform ; pedal region small and short ; siphonal 

 region elongate and broader ; radiatcly rayed with broad, depressed ribs or riblets, which 

 sometimes divide or bifurcate ; ventral margin slightly curved. 



Length, 1 inch. 



Locali/g. Hempstead {Edwards). 



Three specimens of this shell have lately come into the possession of Mr. Edwards, and 

 I think they are entitled to be considered as belonging to a distinct species. The shell is 

 different from M. nodulifera in its more elongated form and in the radiations not being 

 noduliferous. M. pectinata, Lamarck, approaches it in some characters, but the outline is 

 different, and that shell has more numerous radiations. 



8. Modiola hastata, Deshayes. Tab. XII, fig. 6, a, b. 



Modiola hastata. Desk. Coq. Foss. des Env. de Par., t. i, p. 3G1, pi. 38, figs. 13, 14, 

 1824. 



— — Id. All. sans Vert, du Bassin de Par., t. ii, p. 13, 1SG0. 



— elegans. J. Sow., iu Dixon's Geol. of Suss., p. 94, pi. 44, fig. 13, 18.>0. 

 Mytilus jiastatus. Desk. Ency. Method. Vers., t. ii, p. 563, 1830. 



Spec. Char. M. testa ovato-elongatd, subulatd, valde recurvd ; dorso oblique angulatd; 

 striata ; striis divaricatis, spatio medicmo Iccvigafo ; pedi-regione brevi, prof unde crenulatd. 



Shell ovately elongate, tapering, greatly recurved ; dorsal margin obliquely angular ; 

 striated striae divaricating ; central space smooth ; pedal region short, pointed ; margin 

 deeply crenulated. 



Length, \\ inch. 



Localities. Brook {Edwards), Bognor. 



There is a considerable curvature in the ventral margin of this species, and the shell 

 is elevated into an obtuse keel curving from the umbo; in these characters it differs 

 from M. elegans, and it appears to be identical with the Paris basin species. The whole 

 of the siphonal region is deeply and coarsely striated ; these striae bifurcate towards the 

 siphoni-lateral margin, and extend a little over the obtuse keel or ridge, beyond which 

 they immediately become finer, and are soon lost in the naked ventral region. The 

 pedal region is very small, angular, or obtusely pointed, and on the margin of this are a 

 few coarse, radiating striae or ridges. The ventral region is strongly marked with lines of 

 growth. 



