3 86 



THE HUMAN SPECIES 



Tailed people do not exist, though they were supposed to 

 till quite recently. Instances of men with tails occur, however, 

 owing to developmental errors during foetal life (Fig. 196). 

 Virchow thought that this could only be considered as a rever- 

 sion to an animal type when there could be shown to be an 

 actual increase in the length of the spine. He did not consider 

 every case in which the terminal portion of the spine and its 

 coverings were free as reversions, still less the tails composed 

 of soft parts only which he compared to stumps of tails. Bartels, 

 Wiedersheim and Ornstein explain their origin differently. 

 Since embryologists admit that man has descended from 

 ancestors who had free tails, the tails, often I2'5 cm. long 

 (nearly 5 inches), consisting of connective tissue, fat and blood 



vessels, can only be ex- 

 plained as a prolongation 

 of the so-called tail-fibres, 

 and the large overgrown 

 vertebral tail consisting of 

 a joint-like elongation of 

 the caudal spine must be re- 

 garded as a reversion. Man 

 is not the only animal in 

 which these reversions oc- 

 cur ; they have also been 



FIG. ic 



Tail on a boy, six months old. 

 (Granville Harrison.) 



observed in the Inuus ecan- 

 datus, the gorilla, the orang and the chimpanzee. 



(c) Deformities due to supernumerary parts are usually 

 noticed in an increase in the number of the fingers, toes, 

 vertebrae, ribs, breasts, teeth and jaws, but also occur in the 

 internal parts such as the tongue, spleen, etc. Supernumerary 

 fingers are the most common (Fig. 197), supernumerary toes 

 being next, arid almost as frequent. There may be only a 

 small appendage covered with skin but without bones, or a 

 proper finger with the normal number of phalanges. Usually 

 one digit only (a thumb or little finger) is present, but the 

 number of supernumerary digits may amount to a complete 

 double set. In accordance with the law of correlation, both 

 hands and both feet are equally deformed, and the malfor- 

 mation is hereditary and is present in several 'generations. Ac- 



