The Skeleton 51 
five vertebre, which may be separated into the 
usual regions; there are nine cervical, ten dorsal, five 
lumbar, twosacral, and about thirty-ninecaudal. It 
is likely that the number of caudals may be sub- 
ject to frequent variation; one complete skeleton 
had sixty-five vertebre in all, another had sixty- 
eight. A complete skeleton of the crocodile (species 
not known) had sixty vertebre. A thirteen-foot 
skeleton at Western Reserve University had only 
sixty-one vertebra, but some of the caudals were 
evidently missing. Two skeletons of C. porosus in 
the museum at Singapore had sixty and sixty-three 
vertebre respectively. A skeleton of Tomistoma 
schlegali in the same museum had sixty vertebre. 
The Cervical Vertebre. Since all of the cervical 
vertebree bear ribs, we shall assume the distinction 
between them and the dorsal vertebre to be that 
the ribs of the latter meet the sternum, while those 
of the former do not reach to the sternum. As- 
suming this distinction, there are, as was said 
above, nine cervical vertebre. 
With the exception of the first two, to be dis- 
cussed later, these are all essentially alike and the 
fourth will be described as a type (Fig. 17). Its 
centrum is cylindrical or somewhat hourglass 
shaped, concave anteriorly and convex posteriorly; 
it is not completely fused with the neural arch but 
is united with it by sutures. From the anterior 
end of the ventral surface of the centrum projects 
downward and forward a small plow-shaped process, 
