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bulletin of the bureau of fisheries 
tissue, which stains the characteristic blue with Mallory’s connective tissue stain. Its 
composition in the intestine is apparently the same as in the stomach. The inner 
surface of this stratum, that is, the surface toward the middle of the lumen of the intes- 
tine, is marked by a few smaller strands of the same peculiar type of connective tissue. 
The outer surface of the stratum has two or three times as many of these smaller strands. 
A distinct network is formed by the strands extending over to the circular muscle coat. 
In the intestinal region the number and complexity of arrangement of the strands 
composing the stratum compactum is about 40 to 50 per cent as great as in the stomach. 
Nowhere does there seem to be any direct opening or break through the thicker 
portion of the stratum compactum, except where blood vessels penetrate this coat, a 
point which Gulland has made in his study of the stratum compactum of the stomach 
of Salmo solar. It may very well be, as Oppel suggests, that the stratum compactum 
is a protective supporting membrane. It certainly acts as such for the stratum granu- 
losum in Oncorhynchus, whether or not it forms a supporting structure for the whole 
intestine. 
Stratum granulosum . — The meshes of the stratum compactum directly support 
a layer of the special type of cells which has been described in connection with the 
stomach as the granule cells. This layer, the stratum granulosum, is most dense in 
its arrangement in the outer network of the stratum compactum There are a few 
cells more or less scattered, lying on the inner surface of the same connective tissue 
supporting membrane. The granule cells of the intestine are characterized by the 
same form and size and structural arrangements as described for the granule cells of 
the stomach. Here, also, they possess the uniformly distributed, highly refractive 
granules which take stains in the specific way already described. 
These granule cells form a very definite and characteristic structure in the intestine 
and their appearance and presence indicate some function of a significance which one 
can not escape ascribing to the presence of the granules in the cells, a suggestion that 
has been briefly discussed in connection with the stomach. 
There is no muscularis mucosse present either in the intestine or in the pyloric 
appendages. 
The submucous coat, which characterizes the structure of the walls of the stomach, 
is also absent in the intestine. 
HISTOLOGY of THE MUSCLE COATS. 
The muscle coats of the salmon intestine consist of an inner circular and an outer 
longitudinal coat with the plexus of Auerbach and numerous blood vessels between. 
Mtiscularis circularis . — The inner muscle coat of the intestine consists of fibers 
which run in a circular direction. It is a relatively well-developed muscle sheath about 
twice as thick as its fellow, the longitudinal muscle. It is composed wholly of smooth 
muscle fibers, the detailed structure of which does not vary in any particular way, so 
far as noted, from the usual type of smooth muscle. A rich vascular supply, consisting 
of smaller blood vessels and capillaries, is present in this coat, the capillaries coming 
quite largely from arterioles present between the two muscle coats. 
