170 EOCENE MOLLUSCA. 



regione obtuse angulatd ; cardine angusto ; dentihus mediocris ; lunula elongatd non valde 

 depressd ; marginibus crenulatis. 



Shell transverse, irregularly quadrangular, tumid or inflated, smooth in part, inequi- 

 lateral ; pedal region the smaller ; siphonal side subquadrilateral or truncated ; beaks 

 obtuse, somewhat elevated ; hinge narrow, with moderate-sized denticles ; lunule elongated, 

 slightly depressed ; margins crenulated. 



Length, f ths of an inch ; height, f ths of an inch. 



Localities, (var. a) White CHff Bay, Isle of Wight, (var. b) Barton. Edioards. 



This appears to be a rare shell. I have seen only one specimen from each locahty. 

 That from Barton is the more perfect, and shows broad ridges in the umbonal region, but 

 they do not extend over the anal area or beyond the obtuse ridge which divides diagonally 

 the siphonal side. The other, from White Cliff Bay, has lost its outer coating, showing 

 a coarse and fibrous structure, from which, I presume, the inner margin is denticulated, 

 although the inside is hidden by the matrix. This in form and appearance has the aspect 

 of Asiarte, but the connector is internal. 



12. Crassatella sulcata, Solander. PI. XXIII, fig. 11 a — c. 



Tellina sulcata, Solander (in Drander), Fossilia Hantoniensia, pi. vii, fig. 89,1 770. 

 Ckassatella sulcata, J. Sowerby. Min. Conch., pi. 345, fig. 1, 1822. 



— — Desk. An. sans Vert, du Bass, de Par., vol. i, p. 747, pi. xx, 



figs. 12—14, 18C0. 



Spec. Char. C. Testa elongato-trigonuld, valde inaquilaterali, convexd, tumidiusculd ; 

 siphoni-regione angulatd, transversim sulcatd ; sulcis profundis ; lunuld ovatd ; cardine 

 angusto, inaqualiter bidentato ; dentibus lateralibus a^igustis, elongatis ; marginibus 

 crenulatis. 



Shell elongately trigonal, very inequilateral, slightly convex, rather thick ; siphoni- 

 lateral margin angulated, transversely or concentrically sulcated; furrows deep, with 

 elevated ridges between them ; lunule acutely ovate ; hinge rather narrow, with unequal 

 denticles, two in each valve ; lateral teeth elongated ; margins with fine crenulations. 



Length, If ths inch ; height, 1 inch. 



Locality. Barton ; (var. gradata) Huntingbridge. 



France : Senlis, Pontoise, Valmondois, &c., Sables moyens (Desh.). 

 Province of Barcelona [Vezian). 



This is one of the most abundant shells at Barton, where the two valves have been 

 often found united ; traces of the epidermis may be observed, but I have not seen the 

 connector. There is much variation in regard to proportional dimensions, some individuals 

 being very short and high comparatively, while others are much elongated ; some of 

 Mr. Edwards' specimens, of which I have had one figured (PI. XXIII, fig. 7 a, b), are 



