BIHANG TILL K. SV. YET.-AKAD. HANDL. BAND 28. AFD. IV. N:0 8. 45 



more or less herbivorous diet thes rule expressed above does 

 not hold good any louger. The small intestine becomes en- 

 larged to 163 % of the standard or more, which is about twice 

 as much as in the nearest insectivorons allies (conf. the table) 

 and the large intestine increases in length to 42 % or more. 

 There can not be any doubt that this increase is due to the 

 changed diet. In the herbivorons Agaraoid Uromastix the 

 small intestine is not so mneh enlarged (only to 131 % of the 

 standard, but in addition to this the large intestine has been 

 subjected to a considerable increase in length (to 88 %) and 

 an enormous increase in width. The influence of the vege- 

 tative diet on the intestinal canal is, however, most conspi- 

 cuous in the herbivorous Iguanids in which the small intes- 

 tine comparatively is twice to thrice as long^ as it is in nor- 

 mal insectivorons lizards. The large intestine has also been 

 provided with a complicated valvular apparatns (rednced in 

 ÄmhJyrhynchus, conf. below), but at the same time acquired 

 a relative length of from two times and a half to more than 

 four times that of a normal insectivorons lizard. 



With regard to the function of the diiferent parts of 

 the intestinal canal I suppose that it might be assumed that 

 the ventricle and the small intestine have essentially similar 

 functions in all lizards. There might, however, be some 

 difference with regard to the ventricle as the pyloric tract is 

 differently developed in different species. About this nothing 

 can with certainty be ascertained before the histological de- 

 tails have become investigated. According to several authors 

 quoted by Oppel^ the intestinal juices of carni-, herbi- and 

 omnivorous animals do not show any differences worth men- 

 tioning in their digestive influence upon albuminates and 

 fat, and amylum is converted into sugar, cane-sugar inverted 

 to glucose. If this holds good for the lizards as well, the 

 question may be raised why is then the small intestine of 

 the herbivorous lizards so much increased in length compared 

 with that of the insectivorons ones? I think that the ex- 

 planation may be found therein that the, in the small intes- 

 tine, digestible parts of the vegetable food, that is chiefly 

 the contents of the plant cellules, are less accessible for the 



^ Brachylophus forms an exception as is already mentioned, but it 

 might be possible that the diet of this animal is mixed. 



^ The cited work: »zweiter Teil. Schlund und Darm.> Jena 1^97 

 p. 495. 



