140 COMl'AniSOXS of STHUCTURE in ANnULS. 



motion of any heavy animal, as the ox, -we 

 shall find the flexibility of the vertebral 

 column — at kast of its dorsal and lumbar 

 portions — to be very restricted, and its centre 

 of motion indefinite: it seems destitute of that 

 suppleness which we see so marked in the 

 ■weasel or the cat. Now if the dorsal and 

 lumbar vertebrte be examined, they Avill be 

 found short, and with only a thin layer of 

 elastic cartilage intervening between their 

 bodies, while their large strong spinous pro- 

 cesses have no point between them to which 

 they definitely converge. In animals endowed 

 with great flexibility of body, as the cat, the 

 leopard, and others, this converging point is 

 clearly marked, and the oblique bearing in 

 an opposing direction of the dorsal and lumbar 

 vertebra is very decided : added to which the 

 bodies of the vertebra? are comparatively 

 longer, and the layer of cartilage interposing 

 between each is of greater thickness relatively 

 than in the ox. Some animals have no centre 

 of motion in the back, as the armadillo, the 

 chlamyphorus, etc., and in these, the spinous 

 processes are all directed backwards ; (we may 

 here add that such is the case in the elephant.) 

 The progressive motion of snch animals is 



