214 R. W. SHUFELDT 



Claus ('85), in defining the spinal formulae in the Chelonia, 

 is somewhat at variance with Gtinther. He states that "unlike 

 the middle (thoracic) region of the vertebral column, the verte- 

 brae of which are firmly connected with the dorsal shield, the 

 cervical and caudal vertebrae are always movable upon one 

 another. The cervical region is exceedingly flexible, and can be 

 more or less completely retracted within the shell; it consists of 

 eight long vertebrae, which are without ribs. The ten rib-bearing 

 vertebrae are followed by two or three sacral vertebrae, which 

 project beneath the carapace, and by a considerable number of 

 very movable caudal vertebrae" (p. 227). 



This sustains Gtinther' s definition of the cervical and dorsal 

 vertebrae with respect to their kind, but not as to their number, 

 for, as pointed out above, the latter authority states that without 

 exception all chelonians possess twelve dorsals and but two 

 sacrals, while Claus says very distinctly that they have but ten 

 dorsals and "two or three sacrals." 



Claus also figures the "skeleton of Cistudo (Emys) europea," 

 in which there are shown, according to his own definition of 

 them, nine cervical vertebrae; eight thoracic or dorsal vertebrae; 

 three sacrals, and some twenty-five caudal vertebrae. Thus, at 

 the very start, we meet two statements quite at variance with 

 each other with respect to the number of vertebrae in the several 

 divisions of the spine in existing chelonians. 



Sir Richard Owen has also given us a figure of the "skeleton 

 of Emys europea" ('66, p. 60, fig. 51), which has been made to 

 possess but seven cervical vertebrae and, apparently, not more 

 than eight dorsals, while in the text he states that "all the eight 

 cervical vertebrae, fig. 51, E, are free, movable, and ribless."^ 



Owen also claims that "three vertebrae form the sacrum" in 

 the Chelonia and mentions no exceptions to it. 



1 In completing this sentence, Owen states that "the fourth of these vertebrae 

 has a much elongated centrum, which is convex at both ends; the eighth is short 

 and broad, with the anterior surface of the body divided into t\^o transversely 

 elongated convexities, and the posterior part of the body forming a single convex 

 surface, divided into two lateral facets; the under part of the centrum is carinate; 

 the neural arch, which is anchylosed to the centrum, is short, broad, obtuse, and 

 over-arched by the broad expanded nuchal plate." 



