ORGANS OF DIGESTION. 417 



lengthened or crescentic form, but a smaller bulk, than in 

 man. 



The colon is most lengthened, smooth, convoluted, nar- 

 row, and even in its parietes, in the lowest lemurs, and be- 

 comes shorter, less convoluted, much wider, and more 

 sacculated in its parietes by longitudinal muscular bands, 

 in the higher simise and in man (130. E. e. g.} The crecum- 

 coli, which is always present, is, like the colon, more nar- 

 row, curved, smooth, and lengthened in the lemurs, where it 

 sometimes exceeds a foot in length ; it is more short, straight, 

 rounded, wide and cancellated, in the simise and man (130. 

 E. d. e.), and in several of the highest genera it is already 

 provided with the vermiform appendix (130. E./l) so cha- 

 racteristic of the human intestine. This narrow glandular 

 appendix is the first coecum developed in the human embryo, 

 and is the form presented by the adult coecum in many of 

 the inferior mammalia. So that while all the essential parts 

 of this complex apparatus of organic life pass through in- 

 numerable phases of development in ascending through the 

 various grades of the animal kingdom, all their diversified 

 forms are alike perfect in their adaptations to the living con- 

 ditions of the species, and man and the monad, at the two 

 extremes of this great series, are alike digestive sacs, moved 

 to and fro in quest of matter to prolong individual existence 

 and that of the race. 



PART IV. E E 



