EVIDENCE FROM TAILS, LIMBS, &* LUNGS OF ANIMALS. 99 



thirty- three joints, our estimate of tails in general might undergo a com- 

 plete revolution. Such an appendage constitutes 

 a veritable fifth hand to that agile denizen of 

 the South American forests. Grasping the bough 

 of a tree with its prehensile tip, he is enabled 

 to swing himself hither and thither, with his 

 hands and feet free and ready for action in any 

 desired direction. He might be inclined to 

 regard his higher neighbours, in which the 

 tail is reduced to a mere rudiment, as degen- 

 erate and reduced creatures when compared 

 with himself and his terminal organisation so 

 much in thoughts and thinking, as we all 

 know, depends upon one's special point of view. 

 It is, of course, a patent fact to any one who 

 will take the trouble to compare the backbone 

 of man with that of a spider monkey, or indeed 

 with the spine of well-nigh any other quadru- 

 ped that the four small bones forming the 

 end of the human spine, and collectively 

 named the coccyx (Fig. 36), represent a rudi- 

 mentary tail. These bones are seen to be 

 degraded and deteriorated in structure when 

 compared with the other joints of the spine 

 (or vertebrae) with the typical structure of t 



which they undoubtedly correspond. As 

 any tail is merely the hinder extension of ''" LUME 

 the vertebrate spine, so the coccyx, repre- 

 senting in its feeble way the terminal part of 

 man's spine, is certainly a veritable appendage 

 of the kind in question. Man is, however, 

 not the only animal in which degradation of 

 the tail exists, and is propagated by descent 

 as a natural condition of animal existence. 

 The Manx cat has a truly rudimentary tail 

 in this latter aspect ; certain higher monkeys 

 (e. g., orang, chimpanzee, and gorilla) 

 possess the merest traces of this appendage ; 

 and tailless varieties of sheep are known, the 

 latter being well exemplified by a Chinese 

 breed in which, as Mr. Darwin, quoting from 

 Pallas, tells us, the tail is reduced " to a little 

 button, suffocated in a manner by fat," It 



should also be remembered that, in lower life, tails of considerable 

 length may dwindlejLpd disappear, leaving their possessors as abso- 



H2 



SACRUM 



COCCYX^ 



FIG. 36. 

 SIDE VIEW OF HUMAN SPINE. 



