526 HISTOLOGY OF SALITARY GLANDS, ETC. OF COLUBEIDiE. 



in the Crotalidse * appears to be absent from the Protero- 

 gljphous Colubridse, but it seems probable that it hasa repre- 

 sentative in those cushions of non-striated muscle-fibres present 

 at the base of the fangs in the Hjdrophiiuse t, through the slit 

 between which the secretion has to pass. 



EXPLANATION OF THE PLATES. 



Plate 34. 

 Fig. 1. Portion of the buccal epithelium oi Bryophis mycterizans, showing the 

 unicellular glands and the striated free border of the cells. x520 J. 



2. Portion of the buccal epithelium of Buiigams ceylonensis. X 520 |. 



3. Buccal epithelium of Bungarus ceylonejisis, viewed from the surface. 



X 520. 



4. Epithelium towards the edge of the mouth of Enhydris Hardwickii. 



X 520. 



5. A few alveoli of the parotid gland of Bipsas ceylonensis. X 400. 



6. An alveolus of the superior labial gland of Bistira cyanocincta. 



X 500. 



7. Portion of four alveoli of the parotid gland of Bistira cyanocincta. 



X 620. 



8. A few alveoli of the parotid gland of Heterodon sp., in the resting 



state. X 520. 



Plate 35. 

 Fig. 9. A few alveoli of the superior labial gland of Heterodon sp., in the 

 resting state. X 520. 

 10. A portion of the superior labial gland of Bipsas ceylonensis, in 

 active secretion. X 520. ;;, 



b.v. Small blood-vessels. 



c.t. Alveolar connective tissue. 



< 1 ,\ Unicellular glands of buccal epithelium. 



p.c. ' Marginal cells,' which replace efiete gland-cells by pro- 

 liferation. 



* S. Weir Mitchell, /. c. p, 15, fig. 6 b, 



+ Gfr. P. Z. S. 1895, p. 821, pi. xlvi. figs. 13 & 14. 



I The two sections here figured were cut especially for the study of the teeth 

 and consequently more than one layer of cells thick. It was therefore not possible 

 to decide whether the striated free border figured as overlying the mouths 

 the goblet-cells really belonged to them or to adjacent cells. 



