106 MESSES. HANCOCK AND ATTHEY ON 



riddled with medullary cavities, until at length it is entirely re- 

 duced to a sort of cellular structure. This curious cellular tissue 

 is continued into the teeth, and forms their central mass, there 

 being apparently no distinct pulp-cavity, or if any, it is confined 

 to the base. This tissue becomes less open as it approaches, 

 and gradually forms a dense layer at the surface of the teeth, 

 in w^hich layer the Haversian canals are as distinct as they are in 

 the bone of the ramus, and the cells, diminished in size, assume 

 their regular elongated form, and at the extreme margin they 

 disappear. This peripheral layer, which represents the denti- 

 nal wall of ordinary teeth, is found to be continuous from tooth 

 to tooth ; it differs, however, in no respect from the dense ex- 

 ternal surface of the ramus. Indeed it is quite evident that the 

 bone of the jaw is continued into and forms the teeth ; they 

 may, therefore, be looked upon as processes of the jaw. We 

 have failed to detect the least trace of enamel on the surface of 

 the teeth. 



A considerable portion of one of the pectoral spines lies near 

 to the crushed head of this species, in which the jaws are dis- 

 tinctly displayed with the teeth interlocked. The spine has lost 

 its distal extremity ; the fragment, however, is flattened towards 

 this end ; at the basal extremity it is thickened, and assumes a 

 triangular form ; a groove extends along the anterior margin. 

 Detached spines have also occurred, agreeing exactly with Sir P. 

 Egerton's description of the pectoral spine of this species. 



The scales are minute rhombs, with the upper surface smooth 

 and slightly convex. Some appear to be minutely and irregu- 

 larly granulated. Perfectly similar scales clothe the heterocercal 

 tail which was procured at Newsham, and which we believe to 

 belong to this fish. It is about fths of an inch wide, and, in- 

 cluding the pedicle to which it is attached, it is If inches long ; 

 the under lobe is not much produced, and the upper is rather 

 obtuse ; no rays are perceptible. The scales are well preserved, 

 and are in an undisturbed state. Some of them are brilliantly 

 glossy, and have, towards the posterior angle, a boss-like swel- 

 ling ; others are dull and minutely granular. Which is the true 

 natural surface it is difficult to say, though it seems probable 



