194 MR. n. a. seelbt on osseous resemblances 



Grerman Salamander. The transverse processes are directed 

 backward ; and tlie chevron bones of tbe tail are anchylosed to the 

 centrum. 



The scapula and coracoid are the only elements of the pec- 

 toral girdle ossified in Salamanders ; the coracoids are widely di- 

 vided by cartilage. There is a general correspondence of this 

 part of the pectoral arch to that of Skink, except that the acro- 

 mion in Salamander is a very wide short process which unites 

 along its length with the coracoid. The latter bone has much 

 the form seen in Hattetna. 



The humerus and femur are both distinguished by the curious 

 digital trochanters of their proximal ends. "With regard to the 

 other bones, along with a general resemblance of form, which from 

 the absence of epiphyses cannot be traced in the articulations, 

 there is a greater tendency in the bones to enlarge at the distal 

 end than is the case with Lizards. 



The ilium has the Lizard-direction upward and backward ; but, 

 as in Chelouians, it does not extend beyond its transverse 

 process. 



PAET IV. 



THE SIMILITUDES OF 8EEPENTs' BONES. 



The absence of limbs and pectoral and pelvic arches limits com- 

 parisons to the head and vertebral column, which latter is so 

 unlike what is characteristic of other types that the similitudes 

 of Serpents' bones are necessarily few. Little in common with 

 mammals will be noticed beyond the large development of the 

 parietal and frontal bones, and the parietal crest seen in the Boa 

 and Python, of which an analogue may be noticed in Dasyiiribs, 

 Thylacinus, and the Spotted Hyssna. An analogous form of the 

 neural arch, but with the zygapophysial characters which are an- 

 terior in Serpents developed at the posterior end of the arch, occurs 

 in the lumbar vertebrae of Armadillos and Myrjnecophaga ; but 

 the centrum in those animals is unlike that of a serpent's vertebra. 



The resemblances to the bird are chiefly in the large share which 

 the parietals take in covering the brain, and in the function of 

 the frontals in completing the covering in front, in the basisphe- 



