1876.] 



MUCOUS MEMBRANE IN KANGAROOS. 



167 



Obvious characters of the Mucous Membrane. 



With the unassisted eye three distinct regions can be detected in 

 the stomachs of both animals, the mucous membrane presenting well- 

 marked differences in feel, appearance, and, as will be presently seen, 

 in microscopic structure. For the most part they are marked off 

 from each other by distinct lines of demarcation ; these, however, are 

 more obvious between the first and second regions than between the 

 second and third, although, in the latter case also, especially in Dor- 

 copsis, the distinction can be made out even with the naked eye. 



In the two species examined these three regions have somewhat 

 different distributions, as is indicated in the accompanying diagrams. 

 Thus, in Borcopsis (Diagram 1) the first or cardiac region (A), which 



Diagram 1. 



Stomach of Dorcopsis luctuosa. 



is covered with an epithelium obviously continuous with and similar 

 to that of the gullet, occupies more than a third of the inner surface 

 of the organ, lining the whole of the cardiac fundus, and terminating 

 towards the middle of the stomach by a well-marked line of demar- 

 cation ( X ), which extends from the lesser curvature obliquely down- 

 wards and to the left along the anterior and posterior walls to end in 

 the greater curvature about opposite to the opening of the gullet, or a 

 little to the right of that point. Commencing on either side of the 

 cardia two parallel ridges or folds of the mucous membrane (not 

 represented in the diagram) pass for about 3 inches along the lesser 

 curvature, depending into the cavity of the organ. They are little 

 more than half an inch apart, and not quite half an inch in depth ; they 

 become less prominent and gradually subside towards their termina- 

 tion. They bring to mind the ridges which are found in a somewhat 

 similar situation in the Ruminant stomach, but they are by no means 

 so strongly muscular. The second region (B) commences at the ob- 

 lique line above traced out, which separates it from the first or cardiac 

 region, and extends from here to the left, as far as the pylorus, 

 comprehending all the rest of the inner surface of the organ except a 

 circular patch (C) about 2| inches in diameter, which occupies the 



