188 BEPORT — 1841. 



Batrachians. But the most marked difference in this fossil from the crocodile 

 is the length of the ilium posterior to the acetabulum, in which it agrees with 

 the analogous portion of the frog and other tailless Batrachians ; while, on 

 the contrarj'^, there is an agreement with the Crocodilian type in the mode of 

 articulation to the vertebral column. In the frog a transverse process of a 

 single vertebra abuts against the anterior extremity of the produced ilium. 

 In the crocodile the transverse processes of two vertebrae are thickened and 

 expanded, and joined to a rough, concave, articular surface occupying the 

 inner side of the ilium, and a little posterior to the acetabular cavity. In the 

 Labi/rinthodon is a similar well-marked, rough, elongated, concave, articular 

 surface, divided by a non-articular surface, and destined lor the reception of 

 the external extremities of two sacral ribs. The Labyrinthodon likewise 

 agrees with the crocodile in the lower part of the acetabulum being com- 

 pleted by the upper extremity of the pubis, the anterior and inferior part of 

 the ilium oifering an obtuse process at the posterior part of the lower boun- 

 dary of the acetabular cavity. 



As the fragment of the ilium was discovered in the same quarry as the two 

 fragments of the cranium and the portion of the lower jaws, it is probable 

 that they niay have belonged to the same animal ; and if so, as the portions 

 of the head correspond in size with those of the head of a crocodile six or 

 seven feet in length, but the acetabular cavity with tliat of a crocodile twenty- 

 five feet in length, then the hinder extremities of the Labyrinthodon must 

 have been of disproportionate magnitude compared with those of existing Sau- 

 rians, but of approximate magnitude with some of the living anourous Batra- 

 chians. That such a reptile, of a size equal to that of the species whose re- 

 mains have just been described, existed at the period of the formation of the 

 New Red Sandstone, is abundantly manifested by the remains of those singu- 

 lar impressions to which the term Cheirotheriiim has been applied. Other 

 impressions, as those of the Clieirotherium Hercules, correspond in size with 

 the remains of the Labyrinthodon Salamandr aides, which have been dis- 

 covered at Guy's Cliff. The head of a femur from the same quarry in which 

 the ilium was found exactly fits the acetabulum or the articular cavity of that 

 bone. The two toe-bones, or terminal phalanges, resemble those of Batra- 

 chians in presenting no trace of a nail, and from their size they may be re- 

 ferred to the hind-feet of the L. pachygnathus. 



Thus, all these osseous remains from the Warwick and Leamington sand- 

 stones agree with each other and with the fossil remains of the great Masto- 

 donsaurus Salamandroides of the German keuper in their essentially Batra- 

 chian nature. Now it has been suggested by more than one Palteontologist 

 that the impressions of the Cheirotheriiim may have been the foot-prints of 

 aBatrachian; but, in consequence of the peculiarities of the impressions, it 

 is obvious that the animal must have been quite distinct in the form of its 

 feet from any known Batrachian or other reptile. In the attempt to solve 

 the difficult problem of the nature of the animal which has impressed the 

 New Red Sandstone with the Cheirotherian foot-prints, we cannot overlook 

 the fact that we have in the Labyrinthodon also a Batrachian reptile, differ- 

 ing as remarkably from all other Batrachians, and from every other reptile in 

 the structure of its teeth : both the footsteps and the fossils are, moreover, 

 peculiar to the New Red Sandstone ; and the hypothesis that the footsteps of 

 the Cheirotheriiim are those of the Labyrinthodo7i, which I have proposed in 

 my Memoir read before the Geological Society, may be allowed to be sup- 

 ported by more facts than had before been brought to bear upon the question. 



Labyrinthodon scutidatiis. — The remains, to Avhich this specific designation 

 has been applied, composed a closely and irregularly aggregated group of 

 bones imbedded in sandstone, and manifestly belonging to the same skeleton; 



