9 6 



THE HUMAN SPECIES 



basement membrane, and corium) (see Fig. 49), man shares with 

 the other vertebrates, from the fishes to the mammals, but in 

 spite of an extensive general correspondence, on histological 

 examination the human skin presents, nevertheless, certain 

 peculiarities in one direction or another, as well as finer dis- 

 tinctions. 



To the ordinary observer the chief distinguishing feature of 



M. biceps femor. 

 M. plantaris 



M. gastrocnemius 



M. peron. long. 

 M. flex. hall. long. 



Lig. mall, lateralis 

 M. peron. brevis 



Tendo Achillis 



M. semimembranosus 

 M. semitendinosus 

 M. sartorius 

 M. gracilis 



M. plantaris 



M. flex, digit, longus 



M. tibialis posterior 



FIG. 48. Muscles of human calf. (Heitzmann-Zuckerkandl.) 



man as opposed to most of the mammals (with the exception 

 of the whale, dolphin, dugong, hippopotamus and rhinoceros) 

 is the comparative nakedness of his skin, only the beard, 

 head, pubes and axilla being covered with hair. But this is 

 not strictly true, for on a closer examination. of the surface of 

 the body we find that it is everywhere covered with very fine 

 hairs, even in the apparently smooth face of a girl, and these 



