232 MOLLUSCA FROM THE CRAG. 



Spec. Char. Testa orbiculalo-ovatd, tumidd soliduld ; antice rotundatd, postice subangu- 

 latd ; car dine bidentato, dentibus later alibus nuttis. 



Shell roundly ovate, tumid, thick, and strong ; anterior side rounded, posterior 

 somewhat angulated ; cardinal teeth two, lateral teeth none. 



Length, -f inch. Height, f inch. 



Locality. Mam. Crag, Bramerton, Weybourne, Bridlington, Dalmuir, Russia, 

 Canada. 



Recent, Britain, Baltic, N. E. Coast of America, Black Sea. 



I have not seen this shell from the Red Crag ; as it is, however, an estuary species, 

 it is less likely to be there. In the recent state, it is often found high up in our rivers, 

 where the water is nearly fresh when the tide is out. The shells grow large and 

 thick in muddy localities, and thinner and more delicate in sandy places. 



Tellina, is probably its most appropriate place, although the entire absence of lateral 

 teeth does not strictly accord with the diagnosis of this genus, but it corresponds with 

 it in all other respects. 



Fig. 1 a, b, is the representation of a shell from Clacton, where I obtained it from the 

 Clay in which Unio littoralis is found in abundance; and upon some of my specimens of 

 Unio are several barnacles, evidently showing the close proximity of the sea to this 

 fresh-water deposit when it was formed.* 



I have myself obtained only few specimens of the fossil from Norfolk, but I am 

 informed it is not rare. 



8. TELLINA FABULA, Gronovius. Tab. XXI, fig. 3. 



TELLINA FABULA. Gron. Zoophyl. Gronov., p. 263, No. 4, pi. 18, fig. 9, 1781. 

 Phil. Enum. Moll. Sic., vol. i, p. 26, t. 3, fig. 10, 1836. 



Lyell. Mag. Nat. Hist., vol. iii, new series, p. 327, 1839. 

 G. B. Sow. Thesau. Conch., vol. i, p. 287, pi. 57, fig. 62. 

 Forb. and Hani. Hist. Brit. Moll., vol. i, p. 302, t. 19, fig. 9. 



DISCORS. Pulteney. Hutchin's Dorset, p. 54. 



SEMISTEIATA. Solander, ex Montague. 



Spec. Char. "Testa elongato-ovatd, compressd, transversd subinaquilaterali, tenui ; pos- 

 tice attenuatd, subrostratd, antice majiore rotundatd; valvula sinistra Itevi, dextrd oblique 

 striatd; cardine bidentato, dentibus later atibus parvis." 



Shell transversely elongato-ovate, compressed, sub-inequilateral, thin ; posterior 

 side narrow, and somewhat pointed ; anterior broader, larger, and rounded ; left valve 



* At Clacton I have also obtained Mytilus edulis, Cardium edule, and Trigonella plana, and also a 

 rolled specimen of Melania inquinata (Cerithium melanioides, Sow.). 



