64 MOLLUSCA FROM THE CRAG. 
both extremities, middle space smooth, posterior side of the shell broader than the 
‘anterior. 
Longest Diameter, 5 an inch, 
Locality. Mam. Crag, Chillesford. Recent, Britain and Seas of Norway. 
A specimen strongly resembling this species is in my Cabinet, obtained in the 
native bed of the Mammaliferous or Newer Crag Period. at Chillesford. The shells 
in that deposit are excessively fragile, and are preserved with difficulty. This 
specimen appears also to have lost a portion of its outer surface: there is, however, 
upon the exterior, traces of what the sculpture has been, and as far as it can be observed, 
it seems to correspond with that upon the recent shell, it is, therefore, appropriated to 
the above species without much doubt; and, as its congeners in the same deposit are 
such as we know to be its associates at the present day, it might fairly be expected 
in that Formation. In the recent state it is considered more of a Boreal form, with 
but a limited range to the Southward. The earliest appearance of this species is 
in the upper portion of the Crag, where it seems to have been by no means 
abundant. TI have found it in the recent state upon the shore of the Coast of Suffolk, 
in pools of water, left by the retreat of the tide. 
8. MopioLa RHOMBEA, Berkeley. Tab. VIII, fig. 8. 
Moptota Pripgauxtana. Leach. Zool. Miscel., vol. ii, p. 35, 1815. 
— — Brown. Brit. Conch. Ilust., pl. 29, fig. 9, 1827. 
— RHOMBEA. Berkeley. Zool. Journ., vol. iii, p. 229, Suppl. pl. 18, fig. 1, 1827. 
— — Thorpe. Brit. Mar. Conch., p. 107, 1844. 
— — Brown. Brit. Conch. Illust., 2d ed., p. 78, pl. 39, fig. 17. 
— ASPERULA. S. Wood. Catalogue, 1840. 
CRENELLA RHOMBEA. Ford. and Hanl. Hist. Brit. Shells., vol. ii, p. 208, pl. 44, fig. 3, 
1849. 
Spec. Char. Testa minutd ovato-oblongd vel trapeziformi, tumidd, inflatd, crassd ; 
costulato-striatd, sulcis vel strus divaricatis ; anticé abbreviatd, rotundatd, posticé majiore, 
angulata ; margine ventrali sinuato ; natibus prominulis incurvis. 
Shell small ovato-oblong or trapeziform, tumid, or inflated, covered all over with 
large or costulated bifurcating striz ; anterior side, short and rounded, posterior 
larger, and angulated; ventral margin sinuated, with curved and slightly projecting 
umbones. 
Greatest Diameter, 4th of an inch. 
Locality. Cor. Crag, Sutton. Recent, British Seas, and Coast of Sutherland. 
This is considered by the authors of the ‘ Hist. of Brit. Mollusca,’ as an extremely 
rare shell in the recent state, and somewhat of a modern addition to the A/arine 
Fauna, of the British Isles. Although noticed by Dr. Leach as early as the year 
1815, it has since rarely been met with and seldom seen in the Cabinets of collectors. 
It is not so in the fossil, but is very abundant in the rich depdt of small shells at Sutton. 
