BIVALVIA. 127 
SpHENALIA suBsTRIATA, Mont. Crag Moll., vol. ii, p. 128, Tab. XII, fig. 12 (as d/onta- 
cuta substriata) ; Supplement, ‘Tab. X, fig. 20. 
Localities. Cor. Crag, Sutton, and near Orford. Chillesford Bed, Aldeby. 
The figure in Supplement, Tab. X, represents a small specimen showing a difference in 
form from the full-grown shell, bemg much less inequilateral, the umbo being nearly 
central, which was found by Messrs. Crowfoot and Dowson at Aldeby. Mr. Jeffreys 
says (‘ Brit. Conch.,’ vol. v, p. 177), “the fry of sudstriata are nearly globular, like Kelha 
suborbicularis, with the beak in the middle of the dorsal area.” 
Crypropon rotunpatum, 8. Wood. Crag Moll., vol. u, p. 1385, Tab. XII, fig. 19 
(as C. ferruginosum). 
CRYPTODON ROTUNDATUM, S. Wood. Ann. and Mag. Nat. Hist., 1840, p. 247. 
Conceiving that I had erroneously referred my Crag shell, I applied to Mr. Jefireys 
for the sight of his recent specimens, and he obligingly sent me a suite of ferruginosum, as 
also of Croulinensis for comparison, and I now believe my fossil to be distinct from either, 
although it more closely resembles the latter species. Both ferruginosum and Croulinensis 
are united by Forbes and Hanley, but if the two be recognised by conchologists I must 
consider my shell as distinct from either. ‘The Crag form differs from Croulimensis in the 
hinge region, that shell being destitute of the depression possessed by the Crag one on the 
anterior side of the umbo, and from /erruginosum in its obliquity. It is not improbable 
that the Crag shell was the common ancestor of both the living species. I have, there- 
fore, restored to my Crag form the name originally given to it in my ‘ Catalogue of Shells 
from the Crag of 1840.’ I know it only from the Coralline Crag at Sutton, and there it 
is very rare. 
Loriprs pivaricatus, Zinn. Crag Moll., vol. ii, p. 137, Tab. XII, fig. 4. 
Localities. Red Crag, Sutton. Fluvio-marine Crag, Bramerton and ‘Thorpe. 
Middle Glacial, Hopton. . 
This shell has not appeared in the oldest part of the Red Crag, that of Walton, nor is 
it common in the newer portions. It is not uncommon in one of the pits at Bramerton, 
but has not yet occurred in the Chillesford bed at any of its localities. One perfect 
valve and some fragments have been obtained from the Middle Glacial sand. 
The fragment represented in Supplemental Tab. X, fig. 18, was figured under the 
idea that it belonged to Loripes Jacteus, Linn.; but a re-examination of it has induced me 
to doubt whether it be anything more than a fragment of some other bivalve in which a 
