8o 
BUI.LETIN OF THE BUREAU OF FISHERIES 
The superficial epithelial cells undoubtedly serve for the function of absorption 
throughout the full extent of their surface, even down into the depths of the crypts. 
This is proven in at least one instance, i. e., for the fats, as detailed in a later report 
of this series. Fat in process of absorption was found in the cylindrical cells down 
in the bottoms of the crypts, as well as in those cells on the free surface of the gastric 
epithelial coat. 
The epithelial coat of the cardiac stomach is very thick because of the presence 
of the numerous gastric glands. The gastric glands are of the tubular type, though 
they are very irregular as to their position, size, and general arrangement. The glands 
are diverticula of the superficial crypts described above. Each crypt receives the open- 
ings from a number of the gastric glands. The openings are as a rule more numerous 
and more prominent over the bottoms of the crypts, but many glands open into the sides 
of and about the rims of the crypts. At the bottom of the average crypt there is a cluster 
of from three to six glands, the mouths of which open together or sometimes separately 
into the crypt. In the deeper lying crypts glands are more often to be found opening 
into the side of a crypt near its middle, or even near its superficial portion, than in those 
crypts located over the surface of a gross mucous ridge. These latter glands are very 
short and compact, and they are very irregular in shape and often oval in cross section. 
The size of the gastric glands varies greatly, depending on their exact position. 
The more superficial glands are smaller and the deep ones larger and longer. The 
variation is due not so much to the size of the gland cells as to the number in the tube, 
yet there is greater variation in the size of the cells than noted for higher vertebrates. 
The gland tubes are not always linear, on the contrary they are bent and very irregu- 
lar in their extent. In the younger salmon the glands are more tubular as a rule, but 
older examples are often noted in which the tubes are bilobed at the blind end, or have 
one or more diverticula in the side walls. A cross section of such a mass of tubes pre- 
sents very diverse and irregular outlines. 
The gland cells are of a single type and are irregularly polygonal in shape, similar 
to the chief cells in the peptic glands of higher vertebrates. The cells are somewhat 
larger in the salmon, averaging 12 to 20 /i long by 9 to 18 in greatest width. In a 
cross section of a tube the cells do not approximate each other so closely as in the higher 
vertebrates, thus forming a wider lumen. (See fig. 4, pi. xxvi.) 
The nuclei of the gastric secreting cells are slightly oval, almost spherical and rather 
large, with a nucleur diameter of from 5 to 6 /,(. They are located near the bases of the 
cells. The cytoplasm of the gastric gland cells is highly granular, being filled with doubly 
refractive rather small zymogen granules. Special study has not been made of the 
chemical character of these granules. It has been noted, however, that the granules 
are relatively very small and that they stain in the characteristic way with eosin and with 
iron hasmatoxylin. The zymogen granules take these stains lightly and the technique 
must be followed with considerable care. The granules vary in numbers in the glands 
of different fishes from the feeding grounds, presumably, as Gulland suggests for Salmo 
salar, in relation to the stage of the progress of secretion and digestion. In certain 
