120 THE CANCELLI OF BONES 



these individual instances are subservient and 

 this involves the necessity of inquiring, to what 

 extent similar structures exist in other members 

 of the Mammiferous series? After having made 



o 



numerous sections of the corresponding bones of 

 other animals, scarcely any indications of these 

 peculiar arrangements of the cancelli have been 

 demonstrated. The columnar arrangement of the 

 bony fibres of the vertebrae seems the most com- 

 mon. As a general rule, the strength of the bone 

 seems to be obtained in other mammals at the 

 expense of its lightness, by giving greater thick- 

 ness and density to the outer shell, as well as by 

 stouter cancelli with smaller areolae. The peculiar 

 structure of the neck of the thigh, and of the 

 astragalus, seems to exist in man alone. The only 

 animals in which I have detected any approach to 

 the structure of the neck of the thigh in man are 

 in the two species of anthropoid African apes, the 

 Chimpanzee (Troglodytes niger), and the Enge- 

 ena ( T. gorilla), the two species which stand at 

 the head of the brute creation, and which of all 

 brutes make the nearest approximation to the 

 erect attitude. In these, slight traces of the truss- 

 work described in man exist, but in them as in 

 other animals the shell of the neck is much stouter 

 and thicker. 



The structures which have been described in 

 this communication are found mainly, if not 



