270 Messrs. Hancock & Atthey on Reptile- and Fish-Remains 



Besides the above, we have also obtained from the same loca- 

 lity portions of three other mandibles : one belongs to the left 

 ramus, and is in a bad condition ; two are in a good state of 

 preservation, but, unfortunately, they both represent the same 

 portion of the right ramus, the anterior part of each being 

 wanting, as also the proximal extremity. They each measure 

 about six inches in length, and widen a little backwards, where 

 they are two and a half inches broad. If we add to the length 

 of these fragments that of the anterior portion before described, 

 and allow for the parts that are wanting, it would appear that 

 the ramus could not be less than twelve or thirteen inches 

 long. The internal cartilage having been removed, the lateral 

 bony walls have collapsed and are inclined inwards. The jaw 

 is consequently comparatively thin and flattened. The external 

 surface exhibits the peculiar ornamentation in a very beautiful 

 manner. It is the same as on the other bones, the sculpturing 

 extending over the whole surface in the form of smooth ele- 

 vated ridges composing an irregular reticulation, with the 

 meshes or depressed spaces deep and of various forms, fre- 

 quently angular, sometimes rounded, but most commonly 

 elongated ; so that the reticulated ridges, on the whole, have a 

 somewhat dendritic appearance. This striking embossed or- 

 nament closely resembles that of Lahyr-inthodon leptognathus 

 and Li. pachygnathus', only it is considerably finer*. The 

 inner surface of the bone is smooth, as well as the external 

 border of the alveolar ridge ; and there is a groove along the 

 lower margin extending the whole length of the fragment. 



The teeth exliibit very distinctly on the upper portion or 

 crown the wide, compressed, sharp cutting-edges, and on the 

 base the strong fluting or grooves. In several the points are 

 quite perfect, and are decidedly lancet-shaped. The teeth are 

 anchylosed to the bottoms of shallow pits in the not by any 

 means deep alveolar groove. 



In one of the fragments there are seven teeth ; in the other, 

 four perfect and three imperfect. In the latter the anterior 

 tooth is a little more than half an inch long, and the others 

 gradually diminish in size backwards, and are placed consider- 

 ably apart from each other, the spaces between them being 

 nearly three-eighths of an inch wide. In the other fragment 

 the four most perfect teeth appear to be situated at the poste- 

 rior extremity of the alveolar groove, though the jaw is con- 

 tinued for a considerable distance behind them. The anterior 

 of these four is not quite half an inch long, and the others 

 diminish gradually in size posteriorly, the last being not much 



* See Prof. Owen's paper, Trans. Geol. Soc. ser. 2. vol. vi. pis. 43, 46. 



