176 MESSRS. SCHAFER AND WILLIAMS ON THE [Jan. 18, 



ration of pepsin, we hope that before long tlie results of some com- 

 parative experiments already commenced will enable us to form a 

 definite opinion. 



In the foregoing account we have been induced to enter into what 

 might seem almost unnecessarily minute details with reference to 

 the structure of the gastric mucous membrane in these particular 

 animals, because, as we have already incidentally mentioned, they 

 seemed to us especially well adapted for investigation, partly on 

 account of the well-marked differences between the glands of dif- 

 ferent regions, combined at the same time as they are with many 

 unmistakable features of similarity, partly on account of the ease 

 and certainty with which the regions can be mapped out, and partly 

 also on account of the simplicity of form of the glands, which 

 renders them easy of observation throughout their whole length. 



The identity between the glands of the third region here described 

 and the well-known peptic glands of the stomach has been already 

 incidentally noticed, and is sufficiently obvious. It will doubtless also 

 have suggested itself to most of our readers that the glands here 

 described as occupying the second region in the Kangaroo's stomach, 

 and consequently by far the larger portion of the glandular mucous 

 membrane, resemble in most points of structure those which were 

 until the last few years knowii as the mucous glands of the stomach of 

 Man and the higher Mammalia. But the resemblance is more obvious, 

 both as regards situation and structure, in the part of the second 

 region which is near the pylorus, than in the remainder. In the latter 

 the epithelium of the glands presents peculiarities which have not 

 hitherto, it is believed, been noticed in the gastric glands of other 

 animals. These peculiarities are not improbably connected with the 

 nature of the food on which the Kangaroo subsists. Further inves- 

 tigation is necessary to show to what extent they are found in other 

 animals in which the food is similar. 



DESCRIPTION OF THE PLATES. 

 Plate VIII. 



Fig. 1. Vertical section of the mucous membrane of the stomach of Macropus 

 giganteus, carried across the line of junction between the first and 

 second regions. Magnified about 135 diameters. A, end of first region 

 or region of stratified epithelivim ; B, commencement of second region ; 

 X , junction of the two ; <S, stratified epithelium ; p, p, papillce of co- 

 rium rising up into this ; c', lowermost columnar cells of the Mal- 

 pighian layer of the stratified epithelium ; h, horny layer of ditto ; 

 Ig, lymphoid corpuscles between the cells of the Malpighian layer ; 

 gl, tubular glands of mucous membrane of second region ; o, o, their 

 orifices ; c, coliunnar epithelium of the surface ; i, i, interglaudular 

 tissue with numerous lymphoid cells ; m.m, muscularis mucosae ; v, 

 blood-vessels cut across. 



Plate IX. 



Pig. 2. Vertical section of a part of the second region of the mucous membrane, 

 showing three of the tubular glands, of Maoropus giganteus. Magnified 



