LIFE HISTORY OF DESMOGNATHUS FUSCA. 305 



charge their contents into the lumen of the gland, where they 

 form into a fluid which may often be seen in the sections in the 

 process of being discharged through the gland duct. The 

 discharge of the granular contents of the gland cells seems to 

 involve a rupture of the cell membrane. The giant cells, on the 

 other hand, seldom appear to be discharging their granules even 

 when the remainder of the gland shows great activity, although 

 the membranes of a group of such cells not infrequently appear 

 to be ruptured, and a large accumulation of granules to be ready 

 to be discharged. When, however, a larva is killed after having 

 been subjected to much mechanical stimulation in the nature of 

 poking and seizing with the forceps, not only are the ordinary 

 gland cells found empty or nearly so, but the giant cells also are 

 empty and the mass of cells, separated from the rest of the gland 

 by its sheath, is collapsed (Fig. 15, d). It thus seems that these 

 giant cells are in the nature of a reserve supply, ready for instant 

 response in an extreme emergency when the constant secretive 

 action of the ordinary gland cells is inadequate. The only other 

 possible explanation is that the secretions of the ordinary and 

 the giant cells are different in function, a supposition which may 

 upon further investigation prove to be correct, although the 

 appearance of the secretions within the cells gives no indication 

 of such a difference. 



The condition of the nuclei of the gland cells in the fully dis- 

 charged condition does not in the least indicate that the cells are 

 doomed to degeneration; the nuclei are large and round and 

 appear fully vigorous, much like the nuclei of the epidermal 

 cells. Neither does it appear that there is any provision for 

 the replacement of glands during the larval life, either in the 

 form of single replacement cells or the anlagen of new glands; 

 and, as all the glands, both large and small, are equally mature 

 and active and exist in practically the same numbers throughout 

 the whole larval life, there is no chance for the supposition 

 that the small ones grow into the large ones. We are forced, then, 

 to the belief that the larva hatches fully equipped with a set of 

 glands of the granular type that are to perform their function 

 without renewal throughout the many months of larval life. 



That this function is important is very evident, though its 



