264 FOSSIL REPTILES. 



alternate with the bodies of the vertebrae, and do not correspond 

 to them directly. 



The ribs catch in by sutures with these plates. They also 

 catch together through all or a portion of their length. There 

 are eight vertebrae in front, which do not share in this arrange- 

 ment. The first seven, which are the ordinary cervical, are 

 free in their movements. The eighth, which may be consi- 

 dered as the first dorsal, is placed obliquely between the last 

 cervical, and the first of the fixed vertebrae of the dorsal buck- 

 ler, which position shortens it in front. Behind, its spinous 

 process is elongated, and thickens a little to attach itself by 

 sychondrosis to a tubercle on the lower face of the first of the 

 plates of the middle series of the buckler. 



The first of these fixed vertebrae, which is the second dorsal, 

 is rather short, has also its proper annular part, the spinous 

 apophysis of which, shorter than the preceding, attaches itself 

 in like manner to the second plate by a cartilage. 



This second plate, more narrow than the first, makes but 

 one bone with an annular part which is underneath ; the an- 

 terior portion of which is articulated, by two small apophyses, 

 with the articular apophysis of the second dorsal vertebra. It 

 is, then, properly speaking, the annular part of the third 

 dorsal vertebra, but the body of this last is only articulated by 

 its anterior half with the posterior half of this third annular 

 part, while its posterior half is articulated to the anterior half 

 of the fourth annular part. This alternation continues, so 

 that the body of the fourth vertebra corresponds to the annular 

 parts of the third and fourth ; the body of the fifth, to the 

 annular parts of the fourth and fifth, and so on, as far as the 

 tenth. 



The eleventh vertebra after the cervical is the only one 

 which can be called lumbar. It bears no rib. The twelfth 

 and thirteenth are the sacral. To their sides are attached two 

 lateral pieces, swelled at the end to unite to the hinder and 

 upper angle of the iliac bones. Their annular part is close 



