46 INTESTINE AND DIET OF REPTILES. 



digesting juices protected as they are by the cellmembranes 

 than the animal food. The insects for instance get if not 

 raasticated at least piereed by the ieeth here and there, and 

 broken so that the gastric juices ean penetrate already through 

 the chitinous iutegument and reach the digestible interiör. 

 In addition to this the museular activity of the ventricle 

 breaks the insects to pieces so that the access of the dige- 

 stive juices of the intestine is still more facilitated. The 

 vegetable matter offers more difficulties. Tough as it is it 

 is more resistant as well against the action of the teeth as 

 against the museular activity of the ventricle. The influence 

 of the digestive juices must therefore chiefly take place in 

 an osmotic way, and as this is slow work the food-material 

 ought to be subjected to a longer treatment which is won 

 by the increased length of the small intestine. 



If we now turn to the large intestine and the with the 

 same connected more or less developed coecum it seems per- 

 haps at the first look a little stränge that many insectivo- 

 rous lizards as well are provided with a coecum when such 

 an organ, as a rule, is missing in insectivorous mammals. If 

 the condition is a little more closely considered, however, 

 the presence of a coecum in such lizards is easily explained. 

 It has been said above that even in such species in which the 

 large intestine is quite short a constriction usually is present 

 which divides the organ in two physiologically different por- 

 tions. If the large intestine is cut open the diiference with 

 regard to the contents reveals at once the diiference in func- 

 tion of the two parts. In the anterior or colic tract the con- 

 tents lie comparatively loose und there is usually plenty of 

 fluid. In the rectum again the chitinous remains of insects 

 which form the contents are firmely baked together and dry. 

 It can be concluded from this that the colic tract of the 

 large intestine has an reabsorbing and desiccating function. 

 A great deal of the digestible and useful material has of 

 course been reabsorbed in the small intestine, but this organ 

 is short and its faculty thus limited and in addition to this 

 a good deal of fluid must pass trough the ileocolic opening 

 at the same time as the pieces of chitinous remains many of 

 which are large are squezed through the said o]3ening into 

 the colon. This fluid contains most likely digestible substan- 

 ces and is itself also useful for the animal, the more so as 



