48 HABITS OF "WORMS. CHAP. I. 



lamellae like those in the posterior 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- 

 cretion, or one of only moderately large size, 

 is dissolved in acid, much membranous matter 

 is left, which appears to consist of the remains 

 of the formerly active lamellae. After the 

 formation and expulsion of a large concretion, 

 new lamellae must be developed in some 

 manner. In one section made by my son, the 

 process had apparently commenced, although 

 the gland contained two rather large concre- 

 tions, for near the walls several cylindrical 

 and oval pipes were intersected, which were 

 lined .with cellular matter and were quite 

 filled with free calciferous cells. A great 

 enlargement in one direction of several oval 

 pipes would give rise to the lamellae. 



Besides the free calciferous cells in which 

 no nucleus was visible, other and rather 

 larger free cells were seen on three occasions; 



