Chap. I. CALCIFEROUS GLANDS. 47 



cretion, or one of only moderately laige size 

 is dissolved in acid, much membranous matter 

 is left, which appears to consist of the remains 

 of the formerly active laraellai. 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 ; 

 and these contained a distinct nucleus and 

 nucleolus. They were only so far acted on 

 by acetic acid that the nucleus was thus 

 rendered more distinct, A very small con- 

 cretion was removed from between two of the 

 lamellae within an anterior gland. It was 

 embedded in pulpy cellular matter, with 

 many free calciferous cells, together with a 



