16 HABITS OF WORMS. Chap. I. 



resembled an olive-oil flask in shape. These 

 concretions when broken are seen to be 

 more or less crystalline in structure. How 

 they escape from the gland is a marvel ; but 

 that they do escape is certain, for they are 

 often found in the gizzard, intestines, and 

 in the castings of worms, both with those 

 kept in confinement and those in a state of 

 nature. 



Claparede says very little about the 

 structure of the two anterior glands, and he 

 supposes that the calcareous matter of which 

 the concretions are formed is derived from 

 the four posterior glands. But if an anterior 

 gland which contains only small concretions 

 is placed in acetic acid and afterwards 

 dissected, or if sections are made of such 

 a gland without being treated with acid, 

 lamellae like those in the poslerior glands 

 and coated with cellular matter could be 

 plainly seen, together with a multitude of 

 free calciferous cells readily soluble in acetic 

 acid. When a gland is completely filled with 

 a single large concretion, there are no free 

 cells, as these have been all consumed in 

 forming the concretion. But if such a con- 



