﻿BIVALVIA. 



127 



Sphenalia stjbstriata, Mont. Crag Moll., vol. ii, p. 128, Tab. XII, fig. 12 (as Monta- 



cuta suhstriata) ; 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, being 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 suhstriata are nearly globular, like Kellia 

 suborbicularis, with the beak in the middle of the dorsal area." 



Cryptodon rotundatum, S. Wood. Crag Moll., vol. ii, p. 135, 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. Jeffreys 

 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 ferruginosuia 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 Croulinensis 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 ferruginosum 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. 



Loripes divaricatus, Linn. 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 lacteus, 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 



