•280 



FRONTAL SPINE OF HYBODUS 



having been broken off, as well as a small portion of the spine 

 itself; and comes very happily to illustrate some obscure 

 points, which, from the manner in which the former specimen 

 is imbedded in the lias, Mr. Charlesworth was obliged to leave 

 doubtful. I found it myself in the wealden clay, at Sandown, 

 Isle of Wight, between high and low water mark, partially 

 exposed by the washing of the previous tide ; and from the 

 recently fractured surface, it was evident that the spine itself 

 had been broken and washed off by the waves, only a short 

 time before I found it. 



37 



(a) represents the specimen of the natural size, as seen from above, (b c and d) are enlarged 

 views, the first of the under surface, the second of the upper, and the third as seen sideways. 

 (c) is a view of the superior surface of Mr. Charlesworth' s specimen of H. Delabechei described 

 in the last number of the Magazine, of the natural size, introduced for the sake of comparison. 



The dimensions of this specimen are considerably smaller 

 than those of the species figured and described by Mr. 

 Charlesworth, its texture is more compact, and its gene- 

 ral figure more symmetrical. The central process is com- 

 paratively longer, and more regularly formed. It is of a 

 brownish horn colour, smooth and convex on the upper 

 surface, but with a shallow longitudinal depression below, 



