352 MESSRS. HANCOCK AND HOWSE 



determinable, wliile indications of a fifth can be traced. On ac- 

 count of the disturbance of these teeth the central large teeth of 

 four rows are well displayed in profile, being turned over towards 

 the right of the observer, and lying in regular order one behind 

 the other, so that the whole length of the teeth is exposed, the 

 roots being traceable in the matrix. Several of the lateral teeth 

 are scattered on either side, and three or four are removed to 

 some distance to the left. 



This specimen is fortunately broken through transversely near 

 the centre in such a manner that the greater portion of the upper 

 or crushing-disks, with the anterior cutting-margins of one row 

 of teeth, and the backs or under surfaces of another, are finely 

 displayed. And thus we obtain a clear demonstration of the 

 arrangement of the teeth in this fine specimen, and at the same 

 time a complete exposition of the characters of the teeth them- 

 selves. 



A third slab exhibits a dense mass of teeth of an irregularly 

 rounded form, comprising numerous teeth of both jaws (PI. XI., 

 fig. 2). Here, again, the shagreen shows the position in which 

 the body of the fish was deposited ; but as all the teeth have the 

 anterior scoop-like cutting-margins in one direction, there can 

 be no question as to w^hich is front. The specimen rests on the 

 slab with the face uppermost, much as in the last case, only the 

 whole are turned forward, and, unlike it, the teeth are in a much 

 disturbed state, particularly those of the under jaw, which lie 

 uppermost. These, or at least all that remain of them, have 

 been pushed so far forward that they overlie those of the upper 

 jaw towards the left side, leaving exposed the upper surface of 

 the large central tooth and the first lateral of the working row 

 of the upper jaw, which are well exhibited in their true position; 

 and the remains of a second lateral tooth and one or two of the 

 petalodontoid form are seen at the extreme right. These ex- 

 posed teeth of the upper jaw have their crushing-disks and cut- 

 ting-margins turned upwards ; and their roots are well displayed, 

 sinking backwards into the matrix. The few teeth of the under 

 jaw already spoken of on the left have their under surfaces or 

 backs exposed, the crushing-disks being turned down to oppose 



