46 HABITS OF WORMS. CHAP. I. 



and others at first treated them with ether. 

 This produces no effect ; but they are quickly 

 dissolved with effervescence in acetic acid, 

 and when oxalate of ammonia is added to 

 the solution a white precipitate is thrown 

 down. We may therefore conclude that 

 they contain carbonate of lime. If the cells 

 are immersed in a very little acid, they 

 become more transparent, look like ghosts, 

 and are soon lost to view ; but if much acid 

 is added, they disappear instantly. After a 

 very large number have been dissolved, a 

 flocculent residue is left, which apparently 

 consists of the delicate ruptured cell-walls. 

 In the two posterior pairs of glands the 

 carbonate of lime contained in the cells oc- 

 casionally aggregates into small rhombic 

 crystals or into concretions, which lie be- 

 tween the lamellae; but I have seen only 

 one case, and Claparede only a very few 

 such cases. 



The two anterior glands differ a little in 

 shape from the four posterior ones, by being 

 more oval. They differ also conspicuously in 

 .generally containing several small, or two or 

 three larger, or a single very large concre- 



