14 Mr. W. S. Macleay on the Comparative Anatomy 



to the whole spine, the irregularity of the number of vertebrae is 

 so great, that even neighbouring species, — such as the dog and 

 wolf, the camel and dromedary, the horse and quagga, — differ 

 widely in number. Nay more, the same species sometimes 

 presents a variety of number in the vertebral joints. The dif- 

 ference, moreover, between the maximum numbers of vertebrae 

 in Mammalia and birds, as hitherto observed, is 17 in favour of 

 Mammalia ; while the difference between their respective mini- 

 mum numbers, as hitherto observed, is 9, — Mammalia having 

 also the least. Hence, according to what has been said, the 

 differences of the number of vertebrae in Mammalia is of much 

 less consequence, as connected with natural arrangement, than 

 those in birds. 



Now let us watch the general variation of the number of 

 spinal vertebrae in birds ; for which purpose I must construct 

 my tables upon the data afforded by those which are given by 

 M. Cuvier in his Lepons d' Anatomie Comparie, although I am 

 far from conceiving them to be correct. 



Hence, 



