298 



HISTORY OF THE HUMAN BODY 



on the right side, from which there proceed in order an 

 ascending, transverse, and descending portion, connected with 

 the rectum by a sigmoid flexure, through which the tube attains 

 the median line ; a similar disposal is seen in many othei an- 

 thropoids, in lemurs and rodents, the majority of carnivores, 

 and a few others. A more complex condition than this is pro- 

 duced by the formation of long, narrow loops along the 

 course of either the ascending or transverse colons, or both, 

 and these loops may remain simple or roll into spirals. Such 

 colon labyrinths are seen in ruminants, in certain rodents as 

 the lemmings and jumping mice, and in a few lemurs (Figs. 

 83 and 84). 



From this brief review of the alimentary canal and its modi- 

 fications the impression is gained that in this array of enlarge- 

 ments, elongations, diverticula, spiral valves, and other de- 

 vices, we have to do, not with a consecutive anatomical history, 

 but with numerous special cases of physiological adaptations, 

 developed in response to need ; and that a similarity in one of 



Continued from p. 297. 



Comparison of the percentage columns shows that in women there 

 exists a greater tendency towards obliteration than in men. The few dis- 

 crepancies in the table, for example, the smaller average given for men 

 between 50 and 60, and in women between 70 and 80, are doubtless due to 

 the small number of individuals examined. 



