R. R. Bensley 42 131 
The limited cardiac gland area extends all along the junction of the 
two divisions of the stomach, separating the stratified epithelium from 
the glandular area. 
The stomach of the American water-rat or Muskrat, Fiber Jibethicus, 
resembles closely in structure that of Arvicola arvalis as described by 
Retzius, 41, Toepfer, 91, and others. The stratified epithelium which 
is confined in the mouse to the left division of the stomach, in the musk- 
rat passes over into the right division, replacing the glands of the lesser 
curvature, ventral and dorsal surfaces and most of the pyloric glands. 
The fundus glands are confined to a small isolated oval area on the 
summit of the greater curvature, surrounded on all sides by a non- 
glandular mucous membrane covered by tratified squamous epithelium 
which forms a particularly well-marked “ Grenzfalte” on all sides. 
The pyloric glands are not so completely displaced as in Arvicola. 
A small ring-shaped area still remains around the pylorus, from which 
a tongue-shaped mass extends along the lesser curvature in the direction 
of the esophagus. These pyloric glands are separated from the adja- 
cent cutaneous region of the stomach by a “ Grenzfalte” somewhat 
less developed than that surrounding the islet of fundus glands. 
As in the mouse, there is between the “ Grenzfalte” and the fundus 
area on all sides a narrow strip of cardiac glands. These glands have 
neither parietal cells nor ferment-forming chief cells. The cells com- 
posing them contain next the lumen a mass of secretion which stains » 
readily in the usual mucin stains. The secretion does not fill the cells, 
a large protoplasmic proximal zone containing a spherical nucleus being 
usually present. Occasionally, as in the human subject, the glands are 
cystically dilated, in which case the cells are almost wholly protoplasmic. 
The pyloric glands of the muskrat are scarcely distinguishable from 
the cardiac glands, but on the contrary, differ from the glands of Brun- 
ner inasmuch as the cells composing the latter are quite filled with 
mucin, and possess a flattened crescentic or irregular nucleus. 
An interesting fact in connection with the stomach of the muskrat 
is that the fundus glands which are nearest the pylorus exhibit a struc- 
ture similar to that of the fundus glands of the pig, inasmuch as mu- 
cous cells occur not only in the neck of the gland but are frequent 
among the ferment-forming chief cells of the bottom of the gland. 
In addition to the animals included in the preceding description, 
which were selected because they have an important bearing on the 
discussion of the phylogenetic significance of the cardiac gland with 
which this paper will be concluded, I have examined the cardiac glands 
of a number of other placentals and of one marsupial, for example, the 
