THE SALIVAKT AND OTHER GLANDS OF THE COLUBRID^. 521 



tinguisliable from the superior labial glaud), a portion of the 

 gland of DryopMs prasinus (after a period of activity) having 

 been figured*. The difference in structure of the parotid in 

 these two classes of Colubrine Snakes is almost inappreciable, 

 whereas the difference between the structure as exhibited in 

 these two groups and that found in the Proteroglyphous Colu- 

 bridse (and Viperid^e) is most marked. Fig. 8 represents a 

 portion of the gland of Heterodon sp. (one of the Aglvphous 

 Colubridae) during a period of rest ; the cells are fully charged 

 with secretion, the cell-contours and the lumen of the alveoli 

 being almost obliterated. I also figure a few alveoli of the gland 

 of Dipsas ceylonensis (one of the Opisthoglyphous Colu bridge), 

 after a period of activity (fig. 5), in which the cell-contours are 

 very disiinct and a few marginal ceils {p.c.) are present ; these 

 can only be regarded as young cells destined to effect a replace- 

 ment of the eftete gland-cells. Thus it appears that proliferating 

 cells are not confined to mucous glands, but are present to 

 a smaller extent in serous or albuminous glands, in which the 

 destruction of cells and consequent demand for new ones is not 

 so great. 



In the Proteroglyphous Colubrine Snakes the alveoli of the 

 gland are much larger and have a lining epithelium of short 

 columnar cells enclosing a capacious lumen in which the 

 secretion is stored. The grosser structure as found in Naja 

 Jiaje has been well described by Emery t, and also by Martin i 

 in Pseudechis porphyriaciis ; and I find precisely the same type 

 of structure in Bungarus ceylonensis, SJlaps corallinus, Fetro- 

 dymon cucuUatum, and Brachysoma diadema. The supporting 

 framework of inter-alveolar connective tissue varies in amount 

 in different species, but in all cases it is developed to a greater 

 extent in the centre of the gland in the region of the forwardly 

 converging ducts. The poison-duct, which is longitudinally 

 folded for the greater part of its course, has opening into it, 

 throughout its length, a series of small glands which completely 

 surround it, and Emery's supposition that in Ifaja haje these 

 small lobules (which he terms " Schleimdrhsen ? ") are mucous 



« L. c. pi. xliv. fig. 17. 



t Emery, Carlo : " Ueber den feineren Bau der Giftdriise der Naja haje" 

 Archiv f'lir iiiikr. Anat. 1875, pp. 561-568, t. xxxiii. 



\ C. J. Martin, " Snakes, Snake Poisons and Snake Bites," Hermes Med. 

 Suppl. Journ. Sydney Univ. Med. Soc, Dec. 1895. 



