66 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Dec. 3, 



Double transverse processes, the upper more particularly connected 

 with the neural arch, and the lower with the body of the vertebra, 

 are to be found, though the circumstance does not seem to have re- 

 ceived much notice from palaeontologists, in several genera of Sauro- 

 batrachia, or Salamandroid Amphibians. 



In Salamandra maculosa, for example, each cervico-dorsal vertebra, 

 except the atlas, has, on each rib, a prominent transverse process 

 inclined backwards ; and all these processes, except perhaps the very 

 last, are deeply bifid, so as to be divided down nearly to their origin 

 into two more or less divergent processes. The upper division comes 

 off distinctly from the neural arch, while the lower arises for the 

 most part below the level of the upper margin of the articular face 

 of the body of the vertebra. The transverse processes of the three 

 or four anterior caudal vertebrae are also bifurcated at their ends, and 

 at the eighth or ninth caudal the transverse processes cease to be 

 distinguishable. 



The proximal ends of the four anterior pairs of ribs are divided 

 into capitular and tubercular processes of nearly equal length, and 

 possess a distinct ' angle,' whence a process is given off upwards and 

 outwards*. In the hinder ribs the tuberculum becomes a little 

 shorter and more slender than the capitulum. In Pleurodeles Waltlii, 

 the vertebral column and the proximal ends of the ribs resemble 

 those of Salamandra maculosa, though the division of the transverse 

 processes is less marked, and the capitulum and the tuberculum of the 

 ribs are not so deeply separated ; indeed, posteriorly, the separating 

 cleft becomes almost obsolete. In Euproctes the division of the trans- 

 verse processes is hardly discernible ; nevertheless there is a rudiment 

 of the angular processes in the anterior ribs. In other Saurobatrachia, 

 a groove on each side, indicating an incipient division of the proxi- 

 mal end of the rib, is not uncommon. In all these cases, I am not aware 

 that the single or bifid character of the transverse processes is cor- 

 related with any notable differences in other parts of the organization. 



It appears to me, then, that the characters of the certainly 

 Labyrinthodont vertebraef made known by von Meyer and Plie- 

 ninger, and in the present paper, are in perfect accordance with the 

 view originally put forward by Professor Owen, that these animals 

 are more closely allied to the Batrachia than to any of the Reptilia 

 proper. But I conceive that the affinities of the Labyrinthodonts 

 are clearly with the Saurobatracliia (and, in some cranial cha- 

 racters, with the Ccecilice), and not with the Anura as was at first 

 suggested ; and, with every deference to the opinion of so great an 

 authority on all that relates to the Labyrinthodonts as von Meyer, 

 I must venture to doubt whether, in any characters, these Amphibia 

 exhibit a real approximation to the Reptilia. 



* Plieningcr notes what appears to be a process of a similar character to this 

 in the ribs of Mastodonsaurus. 



t It does not appear that there is any evidence to show that the vertebra 1 

 ascribed to Labyrinthodon by Professor Owen in his paper on the Warwickshire 

 Labyrinthodonts (Geol. Trans. 1841) are such, while there is much reason to 

 believe they are not. 



