216 MESSRS. HANCOCK AND ATTHEY 



It is impossible to contemplate the structure of the roof of the 

 mouth of this curious Labyrinthodont without being reminded 

 of the arrangement of the parts in that of Siren, Proteus, and 

 Axolotl. The well-armed vomer in particular is very striking. 

 The extensive development of this vomerine armature, and the 

 deficiency of bony maxillae, would seem to ally Batrachiderpeton 

 to Siren and Proteus ; while the relationship of the vomers to 

 the pterygoids, and the form of the latter, are very similar to 

 what obtains in Axolotl. And the alliance with this interesting 

 form would be rendered still stronger if it should turn out that 

 our new genus has really bony maxillae, particularly as the prse- 

 maxillae are armed with teeth. In Siren and Proteus the pras- 

 maxillaries are quite minute, and are devoid of teeth. 



The characters of the praemaxillse in Batrachiderpeton are, as 

 we have seen, only imperfectly displayed, and some doubt as 

 to their form and extent might be entertained. But it would 

 seem likely that in them we see the whole of the bones of the 

 upper jaw, and that they must have stretched outwards and 

 backwards, and have each been united to a membrane or cartil- 

 age (the representative of the maxilla), and in this way have 

 become attached to the under surface of the malar or the lateral 

 cranial bone where it is smooth and seems well fitted for such 

 attachment ; they could not have been attached to the outer 

 edge of it, for it is covered with surface-ornamentation. By 

 this arrangement spaces for the orbits are provided ; and thus, 

 again, our new Labyrinthodont would seem to resemble Siren 

 and Proteus. 



That this is the fact is apparently corroborated by what can 

 be traced of the bones themselves. The praemaxilla of the right 

 side in the more perfect specimen is, as before pointed out, 

 pressed inwards upon the vomer, or rather in front of it. Before, 

 it is wide, and is continuous with the bone of the muzzle, as is 

 proved by the continuation of the surface -ornament. Behind, 

 however, it appears to have been free, and to have terminated 

 in a pointed extremity. On this side, too, the malar is turned 

 inwards ; but its anterior extremity, which is pointed, does not 



