18 HABITS OF WORMS. Chap. I. 



multitude of the larger, free, nucleated cells, 

 and these latter cells were not acted on by 

 acetic acid, while the former were dissolved. 

 From this and other such cases I am led to 

 suspect that the calciferous cells are developed 

 from the larger nucleated ones; but how 

 this is effected was not ascertained. 



When an anterior gland contains several 

 minute concretions, some of these are generally 

 angular or crystalline in outline, while the 

 greater number are rounded with an irregu- 

 lar mulberry-like surface. Calciferous cells 

 adhered to many parts of these mulberry-like 

 masses, and their gradual disappearance could 

 be traced while they still remained attached. 

 It was thus evident that the concretions are 

 formed from the lime contained within the 

 free calciferous cells. As the smaller concre- 

 tions increase in size, they come into contact 

 and unite, thus enclosing the now functionless 

 lamellae ; and by such steps the formation of 

 the largest concretions could be followed. 

 Why the process regularly takes place in the 

 two anterior glands, and only rarely in the 

 four posterior glands is quite unknown. 

 Morren says that these glands disappear 



