312 MESSES. HANCOCK AND ATTHEY 



found in Professor Huxley's species. The vertebrse are about 

 iVtb of an inch in length, and in height ith of an inch, including 

 the dorsal spine ; the height of the caudal vertebrae, measuring 

 from the upper margin of the dorsal spine to the lower margin 

 of the subvertebral bone, is Jth of an inch. The zygapophyses 

 project laterally as well as forward and backward. 



There are slight indications of anterior and posterior limbs ; 

 but the appearances are too vague to be worthy of further no- 

 tice, beyond that a fragment of bone seems to mark the place 

 of the posterior limb near the termination of the trunk- vertebrae. 

 And not far from this point there is also a small bone, which is 

 probably one of the phalanges. 



The length of the specimen, including the head and trunk-ver- 

 tebrae, is only ona-fourth that of the same parts of U. Wandes- 

 fordii ; we may therefore conclude that the latter species is four 

 times the size of U. reticulalus. When perfect, U. Wandesfordii 

 is upwards of 18 inches long; consequently the new species 

 would measure 4^ inches if entire. 



U. reticulatus is evidently closely related to Kerateiyeton, as 

 is proved by the form of the head, the two occipital eornua, and 

 also by the character of the sternal plates : so close, indeed, 

 does this relationship appear to be, that we have some doubt 

 whether it should not be placed in that genus. It is true that 

 no occipital horns were observed in TJ. Wandesfordii ; but the 

 skull of Professor Huxley's specimen was so much crushed and 

 disturbed that much stress cannot be placed on this negative 

 fact ; and the vertebrae of our species resemble more closely 

 those of Urocordylus than they do those of Keraterpeton. More- 

 over, in the latter form there is a perceptible diminution in the 

 size of the nineteenth vertebra, and so on to the tail, while in 

 our species the last of the three caudal vertebrae, the twenty- 

 third or twenty-fourth, is as large as any of the trunk- vertebrae, 

 agreeing in this respect with Urocordylus, and signifying that U. 

 reticulatus has a long and powerful tail, which is the characteris- 

 tic feature of the genus. We have therefore provisionally placed 

 our new species in that genus. 



Another question arises — Is U. reticulatus a distinct species ? 



