518 ME. G. S. WEST OK THE HISTOLO&T 01' 



by those reagents "wliicli were utilized for staining the rest 

 of the cell. The nucleus is an oval, coarsely granulated body, 

 generally embedded in a cup-shaped layer of protoplasm lining 

 the basal portion of the cell. With regard to the staining, very 

 good results were obtained with Safranin and Orange, and Eosin 

 and Dahlia. Another noticeable feature is that in surface view 

 the epithelial cells appear rounded (PI. 34. fig. 3)*, and not poly- 

 gonal as in the case of ordinary columnar epithelium. Many of 

 the secretory cells retain their nucleus (figs. 1 & 2, ep.gl.), and 

 it would appear that whereas these are enabled to again perform 

 their function, an entire cessation of functional activity has 

 taken place in others in which the nucleus had become dislodged 

 (figs. 1 & 2, ep.'gl.'). The latter effete cells are replaced from 

 below by certain proliferating cells set apart for the purpose 

 (fig.2,^.c.)t. 



In the Hydrophiinse, or Marine Snakes, the lining epithelium 

 of the mouth is not so markedly secretory, the gland-cells being 

 narrower columnar cells confined to a few shallow folds of the 

 mucous membrane. 



Towards the sides of the mouth a conspicuous change takes 

 place, the secretory cells become much- fewer, shorter, and 

 broader, and the interstitial cells increase proportionately in 

 number and in length (fig. 4) ; also a more or less definite 

 cuticle appears to be formed over the free borders of the cells, 

 and the secretory cells disappear, being ultimately replaced by 

 rounded-polygonal cells with large granular nuclei. 



The Labial Glands. — The disposition and composite nature of 

 these glands, which are solely mucus-secreting, I have described 

 elsewhere, but I now wish to consider certain points in greater 

 detail. They are developed to the greatest extent in the Agly- 

 phous Colubridse, and to a larger degree in the Opisthoglyphous 

 than in the Proteroglyphous forms ; in the latter there is a 

 marked aggregation of the glandular tissue at the anterior 

 extremity of the upper jaw, more especially noticeable in the 

 Hydrophiinae. In some Opisthoglyphous forms % the superior 



* Polygonal contours could not be detected when specially sought for. 



t Cfr. remarks on the fat-cells of the hepato-pancreas of the Crayfish by 

 J. Frenzel, " Die Mitteldarmdriise des Flusskrebses und die amitotische Zell- 

 theilung," Archiv f. mikr. Anat. 1893, Ed. sli. 



\ Erythrolamprus Msculapii ; cfr. G. S. West, " On two little-known Opistho- 

 glyphous Snakes," Journ. Linn. Soc, Zool. vol. xxv. p. 420 (1896). 



