AIvIMENTARY tract of the king SALMON 
8l 
young salmon “ taken early in the progress of an active stage of digestion these gland 
cells are charged with granules throughout their entire cytoplasm. The granules are 
smaller and less refractive than the granules of the “granule cells” described below. 
The vascular supply of the mucosa of the cardiac division of the stomach has not 
been especially studied by the methods of injection. Enough has been learned, however, 
from the study of histological preparations to determine that there is a comparatively 
rich blood supply to the gastric mucous membrane. Small blood vessels are found 
in the tunica propria just at the bases of the gastric-gland cells, also between the glands 
themselves. Numerous capillaries are found about the bases of the glands and in the 
connective tissue supporting the superficial epithelium in the regions lying just under 
the superficial epithelium and between the crypts, where there is a relatively high con- 
tent of supporting connective tissue. Numerous capillary nets are noted. Ofttimes 
in relatively thick sections capillary nets are noted which resemble somewhat the 
arrangement of smaller blood vessels as demonstrated by Mall. 
Epithelium of the pyloric stomach . — In the pyloric division of the stomach the 
mucosa forms deep folds arranged in a general longitudinal direction. These folds are 
covered throughout with the cylindrical type of epithelial cell. Those portions of the cells 
of the folds bordering on the cavity of the stomach are only slightly different from the 
cells in the deeper grooves between the folds. This difference consists largely in the fact 
that the surface cells are more slender and somewhat more club-shaped, comparable to 
the superficial cells in the cardiac region of the stomach. There are no proper gastric 
glands in this division of the stomach. The pyloric epithelium forms counterfolds with 
a number of shallow epithelial pits in the first two-thirds of this division of the stomach. 
These shallow pits in the mucous epithelium are present occasionally on the sides of the 
walls of the larger longitudinal folds mentioned above. The many apparent pyloric 
glands, as seen in the transverse sections of the pyloric gastric mucosa, are in reality 
only transverse sections of the longitudinal folds. Near the pyloric valve, marking the 
boundary between the stomach and the intestine, the gastric mucosa consists of a series 
of simple longitudinal folds, and no suggestion of pyloric gland-like pits occurs. The 
longitudinal folds are permanent ones, a fact indicated by the somewhat longer and more 
slender cells present on the free borders of the folds. (See fig. 3, pi. xxvi.) This type 
of structure extends to the circular constriction, the pyloric valve, marking the boundary 
between the pyloric stomach and the pyloric intestine.^ 
Tunica propria . — The connective tissue of the stomach mucosa, on which the 
epithelial coat rests, is called the tunica propria. The term is here used to designate 
all that structure between the basement membrane of the epithelium and the stratum 
compactum. The tissue forms an open network varying in general outlines and in 
thickness according to the degree of stretching of the stomach walls. Folds of the 
tunica extend up into the grooves among the gastric glands, forming a supporting net- 
o- Salmon no. 4s and 46, Pacific Grove, July 10 and ii, 1911. These are the salmon that were artificially fed as described in 
later paper (now in manuscript). 
A view of the pyloric valve is given in a figure in the report dealing with the gross anatomical relations in the salmon. 
This transverse section is through the body at a plane just anterior to the pyloric valve. 
