114 S. P. Woodward— Note on Plicatula sigillina. 
manner to identify their source. In Owen’s ‘ British Fossil 
Mammalia’ (p. 520) the neck of a fossil Whale is figured and 
attributed to the Phocena crassidens, although stated by Pro- 
fessor Sedgewick to have been obtained in a Kimmeridge Clay- 
pit near Ely. The improbability of so great antiquity attaching 
to any Cetacean fossil, induced Professor Morris to substitute 
‘ Pleistocene’ for Oolite, in his Catalogue of British Fossils 
(p. 861). But the bone in question, which is preserved at 
Cambridge, has no connection with the Fen Grampus in the 
Stamford Museum. Mr. Seeley has discovered on its surface a 
Plicatula sigillina, proving that it was derived from the Upper 
Greensand, of which a small mass has been detected on the 
surface, in the very pit from whence the fossil was derived. 
EXPLANATION OF THE FIGURES (PART OF PLATE V.). 
. Group of Phicatule on Ananchytes; nat. size. Kent. 
Very young Pheatula; magnified 4 diameters. Kent. 
. Largest specimen; magnified 2 diameters. Norwich. 
Profile of section across the same, from side to side. 
. Small Pheatula, 4, with upper valve broken in the centre. Norwich. 
. Young Ostrea vesiculosa, magnified 2 diameters. Norwich. 
BR COO 
Or 
[oP) 
V. Description oF A New Fossiz Fisn rrom THE LOWER CHALK. 
By Arsert GintHer, M.A., M.D., Ph.D. 
[Plate VI. | 
(HE British Museum has lately received a fossil Fish from 
the Lower Chalk at Folkestone, which appears to be un- 
described, and is probably the type. of a distinct genus. ‘The 
fossil is twenty inches long, with the vertebral column and the 
fins tolerably well preserved, whilst the head unfortunately 
has suffered so much that scarcely any part of it can be dis- 
tincuished. 
What first arrests our attention in examining the specimen, are 
bony plates disposed in longitudinal series, which are extremely 
similar to those of Dercetis and Rhinellus, as figured by Agassiz 
(Recherch. Poiss. foss., vol. 1. pl. 66a, figs. 6 and 7). Although 
the fishes named are also from the Chalk, they belong evidently 
to different genera. Dercetis scutatus is the type of the genus 
Dercetis, and described as having the ventral fins very close to 
the pectorals, short, and composed of five rays only, the dorsal 
and anal fins long, the former occupying nearly the whole of the 
back, the latter the lower part of the tail. In our Fish, on the 
contrary, the ventral is remote from the pectoral, and the dorsal 
and anal are short. The typical specimens on which Agassiz 
has founded the second species, D. elongatus, and which I have 
