128 EOCENE MOLLUSCA. 



:>. Led a oblata, S. Wood. Tab. XIX, fig. 10. 



Spec. Char. L. testa minima, elongato-ovatd, oblata, lavissi/nd, glabra, subeequil fi- 

 le rail ; pedi-regione tumidd; siphonc-regione compressiusculd, margine obtuse rostratd ; 

 umbon ibus prominulis. 



Shell small, elongately ovate, externally smooth and glossy, slightly inequilateral; 

 pedal region tumid and rounded ; siphonal region compressed ; obtusely rostrated ; beaks 

 slightly prominent. 



Length, gi'd of an inch. 



Localities. Chalk Farm {Wetherell), Potter's Bar {Edwards). 



There are a few specimens in Mr. Wetherell's cabinet, and also in Mr. Edwards's, 

 which very much resemble, in outline and general characters, L. partim-striata from 

 Jlighgate and Clarendon; but they differ in having the exterior perfectly smooth and 

 glossy, and appear to be quite free from the ridges which ornament the centre or ventral 

 portion of the shell of that species. This species presents some resemblance to the variety 

 L. prisca, from Highgate; but the shell is larger, and the siphoni-lateral margin is not so 

 pointed. The specimens are too closely imbedded in the clay to permit of removal, 

 and the interior is consequently invisible. 



(i. Leda prisca Deshages. Tab. XVII, fig. 4, a — d. 



Leda prisca. Desk. An. sans Vert, du Bass, de Par., t. i, p. 830, pi. 65, figs. 15 — 17. 



Spec. Char. L. " testa minima, obovatd, tumidd, lavigatd, polild, striis incrementi vix 

 conspicuis ; einlice rotundald ; postice angulatd, acuta, euneatd ; umbonibus submedianis. 

 depressis ; lunula elli plied ; dentibus 8 — 9 utroque angulatis ; marginibus integris." 



Shell small, obovate, tumid, or inflated ; smooth, glossy, with scarcely visible lines of 

 growth; one side rounded and the other angulated and sharp or wedge-shaped; umbones 

 subcentral, depressed ; lunule elliptical ; denticles about 8 — 9 on each side ; margins 

 smooth. 



Length, 7 3 B ths of an inch ; height, T ' th of an inch. 



Localities. Var. a, Highgate {Wether ell) ; var. /3, Barton {Edwards and S. Wood). 



This pretty little shell is by no means abundant. It strongly resembles L. pggmaea, 

 the existing British and Mediterranean species. 



There are two British Eocene shells that I think may be assigned to the French 

 species; they (lifter a little in the number of denticles; the one from IIiol)o ; ,te cor- 

 responds closely with the description given by M. Deshayes ; the other, from Barton, docs 

 not appear to have quite so many teeth in the hinge-line. They both differ from 



