﻿BIVALVIA. 



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This shell I have placed in the genus Lascea, as it corresponds in its dentition with 

 Lascea rubra, and it has not the peculiar ornament of Lepton upon the exterior, but is 

 covered with concentric strise or fine lines of growth. Mr. Jeffreys describes the recent 

 shell as being "marked with longitudinal radiating lines" ('Brit. Conch.,' vol. ii, 

 p. 203) ; these are not visible in my fossil, but my specimens are rare. 



Lascea intermedia, S. Wood. Supplement, Tab. X, fig. 22. 



Localities. Chillesford Bed, Aldeby. Middle Glacial, Hopton. 



The specimen figured was sent to me by Messrs. Crowfoot and Dowson, who found 

 it with some others at Aldeby, and a single perfect specimen of the same species has 

 been found by my son in the Hopton Sand. 



It resembles Lascea pumila of the Cor. Crag in size and outline, but it is much 

 flatter or more compressed, and it differs essentially in its dentition. Our present shell 

 is transversely ovate, very inequilateral, compressed, and with a smooth exterior j the 

 right valve has a rudimentary cardinal tooth and a very elongated lateral tooth on the 

 longer or pedal side, with a small one on the other nearly at right angles ; the left valve 

 has corresponding denticles, but not so prominent. 



At first I thought the present shell might be referred to M. Dawsoni, ' Brit. Conch./ 

 vol. ii, p. 178, but Mr. Jeffreys, who examined the Aldeby specimens, said "this little 

 bivalve is, I consider, the younger state of your Kettia pumila. Montacuta Dawsoni differs 

 from it in being flatter and having no cardinal tooth, the lateral teeth being very much 

 shorter and stronger." The denticles of my shell are much longer than in either pumila or 

 Dawsoni ; and I have, therefore, for the present, kept them distinct. My shell is by 

 no means thin, and the anterior muscle-mark is large and deeply impressed, from which 

 I think it is fnll grown. 



Bornia ovalis, S. Wood. Supplement, Tab. IX, figs. 3 «, b. 



Locality. Cor. Crag, Sutton. 

 Length, -j^-ths of an inch. 



Two specimens, both unfortunately of the same value, have lately been found by 

 myself, and I am unable satisfactorily to refer them to a known species. My shell has 

 two short but prominent diverging teeth, one on each side of the depression for the 

 cartilaginous connector. There is an indentation in the umbo which much resembles 

 that present in some species of Cochlodesma, through which the cartilage protrudes. 

 This opening may have been made in a similar manner, or it may be accidental. 



I have, from these imperfect materials, declined giving a diagnosis. 

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