170 EOCENE MOLLUSCA. 
regione obtuse angulaté ; cardine angusto ; dentibus mediocris ; lunuld elongata 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, $ths of an inch; eight, §ths of an inch. 
Localities. (var. a) White Cliff Bay, Isle of Wight, (var. 4) Barton. Hdwards. 
This appears to be a rare shell. I have seen only one specimen from each locality. 
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 Astarte, but the connector is internal. 
12. CrassaTELLa suLcata, Solander. Pl. XXIII, fig. 11 a—e. 
TELLINA sULCATA, Solander (in Brander). Fossilia Hantoniensia, pl. vii, fig. 89,1 776. 
CrassaTELLa suLcata, J. Sowerby. Main. Conch., pl. 345, fig. 1, 1822. 
_— — Desh. An. sans Vert. du Bass. de Par., vol. i, p. 747, pl. xx, 
figs. 12—14, 1860. 
Spec. Char. C. Testa elongato-trigonuld, valde inequilaterali, convexd, tumidiusculd ; 
siphoni-regione angulatd, transversim sulcatd; sulcis profundis; lunuld ovata; cardine 
angusto, inequaliter bidentato; dentibus lateralibus angustis, 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, \3ths inch ; height, 1 inch. 
Locality. Barton ; (var. gradata) Huntingbridge. 
France: Senlis, Pontoise, Valmondois, &c., Sables moyens (Des/.). 
Province of Barcelona (Vézian). 
his 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 (Pl. XXIII, fig. 7 a, 4), are 
