BBITISH FOSSILS. 



3 



may be, however, that the embryonic character was persistent in 

 the hinder extremity of the column, notwithstanding the ultimate 

 development of its other parts. The scales of this fish are remark- 

 able for their great number and the beauty of their sculpture. The 

 dorso-ventral rows on the flanks contain nearly sixty scales in each. 

 Those on the flanks in the vicinity of the line of the vertebral 

 column (which was nearly straight and equidistant from the back 

 and belly) are larger than the dorsal and ventral scales ; but on 

 the after part of the body they are all of uniform size. The under 

 surface of each scale has a strong process on the upper margin, which 

 corresponds with a pit on the lower margin of the scale above it ; 

 in addition to this, these margins are bevelled, so that additional 

 strength is secured by the overlap of the juxtaposed scales in the 

 dorso-ventral series. The external surface of each scale is orna- 

 mented with five or six raised lines of enamel, some single, some 

 bifurcate. These are most frequent on the scales of the anterior 

 parts of the fish, but they are distinctly developed upon all. These 

 dermal characters agree closely with those of Oxygnathus. The 

 small portions of the jaws which remain show the bases of strong 

 sauroid teeth ; the other parts of the head are deficient. 

 Locality, — Lias of Barrow-on-Soar, Leicestershire. 



Explanation of Plate. 



Fig. 1. Cosmolepis Egertoni, size of nature. 

 Fig. 2. Tail of another specimen. 

 Fig. 3. Outer surface of scales, magnified. 

 Fig. 4. Inner surface of scale, magnified. 



P. DE M. Grey Egerton. 



February 1857. 



