1876.] MUCOUS MEMBRANE IN KANGAROOS. 171 



tinued also into the openings themselves. Tracing it further into 

 the gland, we find the cells, still columnar, less tapering at their 

 fixed extremities ; and, moreover, while in the mouths of the glands, 

 as on the general surface, they stand vertical to the basement 

 membrane with their free ends on the same level, in the throat 

 of the glands, on the other hand, they slant upwards, so that they 

 more or less overlap one another (fig. 2, n). Further downwards 

 in the tube the cells become gradually shorter, so as to appear 

 quadrangular or cubical in form ; at the same time the lumen of the 

 tube becomes much narrowed, and, indeed, in vertical sections of the 

 mucous membrane is in some parts hardly perceptible. These shortly 

 columnar or cubical epithelium-cells occupy the greater part of the 

 length of the tube (m). They have each a very distinct round or 

 oval nucleus with one or two nucleoli ; and the protoplasm of the cell, 

 which is granular in appearance, becomes stained by logwood, 

 although not nearly so intensely as the nucleus. 



Towards the fundus (6) of the gland the cells undergo a change. 

 They become gradually larger, and rounded or polyhedral in shape ; 

 their outlines become more distinct ; and the substance of the cell 

 acquires a clear or very faintly granular aspect, and, moreover, 

 becomes hardly at all stained by logwood. Further, the nuclei, for 

 the most part, have not their usual characteristic vesicular appearance, 

 but in most of the cells (which line, and in some cases almost fill, 

 the fundus) appear as intensely stained, shrunken or compressed 

 bodies, usually situated excentrically in the cell, and not frequently 

 flattened up against the basement membrane. In short, the appear- 

 ance of these polyhedral cells of the fundus of the gland brings 

 strongly to mind the cells which occupy the alveoli of the sali- 

 vary gland (submaxillary) ; and it is not impossible that the clear, 

 swollen-out aspect they present may be due to a cause similar to 

 that to which the salivary cells are believed to owe their characteris- 

 tic appearance, the presence, namely, within the cells at the time 

 of death of mucus or some similar substance, which swells up on 

 the addition of fluid. Or it may be that the protoplasm of these 

 lowermost cells is younger and less changed than that of the other 

 cells of the gland, and consequently that they are more readily acted 

 upon by reagents, or by the secretion of the gland itself after death, 

 than the rest. At any rate there seems a close analogy between the 

 structure of the deeper parts of these tubular glands and the alveoli 

 of the compound racemose glands. At the same time it must be 

 remembered that some of the latter class of glands, the pancreas for 

 example, do not exhibit the clear, swollen-out cells with excentrically 

 placed nuclei, but their alveolar walls resemble more, on the contrary, 

 the cubical cells of the middle parts of the tubular glands above 

 described ; and it is worthy of note that in some parts of the second 

 region of the Kangaroo stomach, those for instance in the neigh- 

 bourhood of the pylorus, the tubular glands, which are here very 

 long, are hned in the deeper as well as in the middle parts, by cubical 

 or shortly columnar cells which are similar throughout. 



The substance of the mucous membrane between the tubular 



