ii.] THE SPINAL SKELETON. -i 



equal, if they do not exceed, the neural spines in length. 

 Hyperapophyses may exist upon the postzygapophyses of 

 the anterior cervical vertebrae, as in the Dog. 



25. In the preponderating size of the LUMBAR VERTEBRAE 

 man but exaggerates a character generally present in his 

 class, but this preponderance is not universal, as is shown bv 

 Bats. Lumbar vertebrae are generally to be distinguished in 

 Mammals, and in Crocodiles and certain Lizards, but not in 

 any Ichthyopsidan. 



In Birds, lumbar vertebrae are present indeed, but disguised 

 and hidden by exaggeration of the sacral anchylosis. 



The number in man is below the average of his class, 

 though some Apes have but four, the Two-toed Sloth but 

 three, and the Monotremes but two. 



The largest number in quadrupeds is eight, or sometimes 

 nine, found in the Slow Lemur which is very remarkable, as 

 in that beast there are also sixteen dorsal vertebrae. There 

 may indeed be as many as twenty-four lumbar, as in the 

 Dolphins, though the limits of the region are somewhat in- 

 determinate in those animals. 



The spinous and transverse processes of the lumbar verte- 

 brae are shorter relatively in man than in most Mammals, 

 which also have them generally directed towards the head. 

 The lumbar transverse processes may be excessively pro- 

 longed, as in Cetaceans, and the last ones may articulate or 

 anchylose with the sacrum, as in the Horse. 



FIG. 65. LUMBAR VERTEBRA OF THE GREAT ARMADILLO (Priodonte^. 

 c, centrum ; s, spine ; /, capitular process ; z ', postzygapophysis ; w, meta- 

 pophysis; a, anapophysis ; x l , x*, x 3 , **, four contiguous but distinct 

 articular surfaces. 



{From the College of Surgeons' Museum*) 



The metapophyses and anapophyses attain their greatest 

 length in the lumbar region : thus in the Armadillos the 

 former processes equal the spinous processes in length, and 

 E 2 



