28 THE VENOM OF HELODERMA. 



perinuclear cytoplasm occupying the basal portion of the cells. In form it is 

 spherical or elliptical, but I have observed no constant relation between the 

 form of the nucleus and the secretory phase of the cell. Shrunken nuclei were 

 observed in cells entirely filled with granules, but in all other cases the nuclei 

 were of approximately the same average size. I have not observed in Helo- 

 derma the changes in the nucleus described by Matthews in the pancreas and 

 by Launaj' in the poison gland of the viper, as associated with the changes in 

 activity of the cell. The nuclei of the active cells, as far as I have observed, 

 show no constant differences from those of the inactive cells. 



The cells of the terminal acini (fig. 12) are slightly smaller than the intra- 

 lobular duct cells. In form they approximate to the cubical type. Their 

 cytoplasm is distinctly alveolar, this structure being clearest on the side facing 

 the lumen. At the base it is much denser, resembling that in the correspond- 

 ing part of an intralobular tubule cell. The large secretory granules, so evi- 

 dent in the latter, are entirely lacking in these cells, though minute granular 

 particles are rather thickly scattered through the cytoplasm. The interspaces 

 of the reticulum are occupied by a clear ground-substance, which failed to stain 

 with the usual mucus stains. The nuclei showed no constant differences from 

 those of the intralobular duct cells. 



