Morphology. 83 



to understand how he had managed to retain an 

 organ which had been renounced by his most recent 

 ancestors. Nevertheless, as the anthropoid apes con- 

 tinue to present the rudimentary vestiges of a tail 

 in a few caudal vertebrae below the integuments, we 

 might well expect to find a similar state of matters in 

 the case of man. And this is just what we do find, as 

 a glance at these two comparative illustrations will 

 show. (Fig. 15.) Moreover, during embryonic life, 

 both of the anthropoid apes and of man, the tail much 



FIG. 16. Diagrammatic outline of the human embryo when about 

 seven weeks old, showing the relations of the limbs and tail to the 

 trunk (after Allen Thomson), r, the radial, and u, the ulnar, border of 

 the hand and fore-arm ; t, the tibial, and f, the fibular, border of the 

 foot and lower leg ; au, ear ; s, spinal cord ; v, umbilical cord ; b t branchial 

 gill-slits ; c , tail. 



more closely resembles that of the lower kinds of 

 quadrumanous animals from which these higher re- 

 presentatives of the group have descended. For at 

 a certain stage of embryonic life the tail, both of apes 

 and of human beings, is actually longer than the legs 

 (see Fig. 16). And at this stage of development, 

 also, the tail admits of being moved by muscles 

 which later on dwindle away. Occasionally, however, 



G 2 



