234 MOLLUSCA FRO:\I THE CRAG. 



This species is exceedingly abundant in the CoraUinc Crag, but I have seen it only 

 in one localit\'. The palleal impression is very large and deep, extending inwards 

 until it almost touches a sort of ridge or thickening of the shell between it and the 

 impression of the anterior adductor ; the lateral teeth are at unequal distances : two 

 obtuse ridges diverge from the umbo to the ventral margin on the siphonal side, most 

 distinct in the right valve, upon the interior of full-grown specimens ; in the left, these 

 markings, instead of being in relief, are impressed. Upon some of my fossils there are 

 the remains of continuous coloured bands, not intercepted by white radiations. None 

 of my Crag specimens have attained to so great a magnitude as is given to the recent 

 British shell, my largest scarcely reaching three fourths of an inch in length. This has 

 been well named : it strongly resembles a Donax in all its characters. 



A specimen, in the cabinet of Sir Charles Lyell, has the locality of Bramerton 

 attached to it. 



10. Tellina donacilla, S. Wood. Tab. XXII, fig. G, a, b. 

 Tellika donacii.la. S. Wood. Catalogue, 1840. 



Spec. Char. Testa transversa, ovato-oblongd, sulinaquilaterali, covipressiusculd, poUtd ; 

 2}0stice breviore, truncatd, biangulatd ; antice rotundatd ; cardine bidentato ; dentibus late- 

 ralibus duoliis. 



Shell transverse, ovately oblong, somewhat inequilateral, compressed, glossy ; 

 posterior side the shorter, truncated, and biangulated ; anterior side rounded ; two 

 cardinal, and two lateral teeth. 



Length, {^ inch. Height, I inch. 



Localitg. Cor. Crag, Sutton. 



This shell appears to be rare, one specimen of each valve, in my own cabinet, are 

 all that I have as yet seen. It very much resembles in outline T. Oudarda, Payr., ' Moll. 

 Cors.,' p. 40, pi. 1, fig. 16 — 18, and I had considered it different, in consequence of 

 the want of the peculiarly characteristic marks of that species, which has the exterior, 

 as stated by the author, beautifully ornamented with lozenge-shaped cancella;, formed 

 by radiating striae intersecting the lines of growth. If these lines be ujjon the 

 recent shell and not alone in the epidermis, our fossil does not possess them. The 

 surface is covered with some broad and flat oljsolcte ridges on the body of the shell, 

 which are sharp and elevated upon the posterior slope. It is flatter than T. donacina, 

 less inequilateral, and has not the fine and regular strife of that species. It also 

 somewhat resembles the figure of T. compressa, Broc, \>\. 12, fig. 9; and may possibly 

 belong to one of the Mediterranean or Subappennine species, but I have not been able 

 to o])tain specimens for comparison. 



Our shell has two diverging cardinal teeth in the right valve, with one large. 



