ALIMENTARY TRACT OP THE KING SALMON 
85 
eosinophile leucocytes.” This identification will not apply to the cells of the king 
salmon for the following reasons: First, the salmon leucocytes are very much smaller 
than the cells in question. Also one never finds a cell of the granule-cell type inside a 
blood vessel, though diligent search has been made. Second, the granule cells form a 
distinct and persistent structure in a definite region of the stomach and alimentary tract. 
It is out of the question that the eosinophiles of the blood should form such a cell group- 
ing in every animal of whatever age. 
Muscularis mucosas . — The muscularis mucosa is present in the salmon stomach. 
It consists of a rather thick double layer of muscle fibers, relatively much thicker than 
the corresponding coat in the mammalia. The fibers run both in the circular and in the 
longitudinal direction. There is much irregularity in the direction of the fibers, due in 
part to the fact that the muscularis mucosae follows the folds of the mucosa rather than 
the outlines of the outer and heavier coats of the stomach. There are many free bundles 
of fibers more or less irregularly disposed in the folds of the submucosa and on the 
external or outer surface of the muscularis. 
In the contracted stomach, in which the mucosa is thrown into deep longitudinal 
ridges, a cross section shows that the muscularis mucosa takes a somewhat sinuous or 
wavy course in its position between the mucous epithelium and the outer muscular 
coats. In places the muscularis will be in contact with the inner or circular muscle 
coat, where its thickness is shown to be from 40 to 60 per cent as great as that of the 
muscularis circularis itself. In the loops of connective tissue between two such points 
of contact between the two muscular coats there are always found the free or isolated 
bundles of muscles mentioned above. These isolated bundles unquestionably belong to 
the muscularis mucosse. 
■HISTOLOGY OP THE GASTRIC SUBMUCOSA. 
The submucosa of the king salmon forms an irregular connective tissue coat between 
the muscularis mucosae and the muscularis circularis. In places the submucosa seems 
quite obliterated and the two muscular coats are in contact. Under the deeper longi- 
tudinal folds of the mucosa the submucosa forms quite extensive masses of loose areolar 
connective tissue. Evidently in the salmon stomach this layer forms an adaptable coat 
for allowing the mucosa to slide over the inner surface of the muscularis circularis or 
vice versa. 
The submucosa contains in its meshes numerous blood vessels of different sizes. 
There are also isolated bundles of muscle fibers from the muscularis mucosse, and a 
sprinkling of granule cells that have wandered from the stratum granulosum. 
HISTOLOGY OF THE GASTRIC MUSCLE COATS. 
The proper muscle coats of the salmon stomach are two in number, the circularis 
and the longitudinalis. Between the two, and rather more deeply embedded in the longi- 
tudinalis, is the plexus of Auerbach, which should be mentioned in this connection. 
Muscularis circularis . — The inner of the two muscle coats is the circular layer. 
It is a well -developed sheet of muscle in the salmon stomach, as shown in every cross 
