26 



REPTILES AND BATRACHIANS. 



along in turn, like a foot, to its special pair of ribs. Just so many 

 vertebra as a snake has in its spinal column, so many ventral 

 plates or scuta there are ; and by these broad under-scales you 

 can always ascertain how many joints there are in the spinal 



Fis:. 8. — Skeleton of a snake. 



column. The very long snakes have three or even four hundred 

 vertebra in their spine, smaller snakes perhaps only one hundred 

 and fifty or two hundred. Where the tail begins the ribs of 

 course cease, but the tail bones are reckoned among the ver- 

 tebra. As a general rule vipers have short tails ; and the long, 



