CHAP. I. CALCIFEEOUS GLANDS. 45 



Calciferous Glands. These glands (see 

 Fig. 1), judging from their size and from their 

 rich supply of blood-vessels, must be of much 

 importance to the animal. But almost as 

 many theories have been advanced on their 

 use as there have been observers. They 

 consist of three pairs, which in the common 

 earth-worm debouch into the alimentary 

 canal in advance of the gizzard, but pos- 

 teriorly to it in Urochaeta and some other 

 genera,* The two posterior pairs are formed 

 by lamellae, which, according to Claparede, 

 are diverticula from the cesophagus.f These 

 lamellae are coated with a pulpy cellular 

 layer, with the outer cells lying free in in- 

 finite numbers. If one of these glands is 

 punctured and squeezed, a quantity of white 

 pulpy matter exudes, consisting of these free 

 cells. They are minute, and vary in diameter 

 from 2 to 6 /x. They contain in their centres 

 a little excessively fine granular matter ; but 

 they look so like oil globules that Claparede 



* Perrier, ' Archives de Zoolog. exper.' July, 1874, pp. 416, 

 419. 



t ' Zeitschrift fur vrissenschaft. Zoologie,' B. xix. 1869, pp. 

 603-606. 



