ALIMENTARY CANAL, ETC., OF AMIURUS CATUS. 403 
relaxed intestine. A partial distension of the midgut with chromic 
acid and alcohol easily demonstrates the connected character or con- 
tinuity of these prominences as longitudinal folds. 
The musculature consists of an outer longitudinal layer with an 
inner one of smooth fibres. The latter is the thickest, and in the 
pyloric valve increases so as to form the constricting muscle. 
The muscularis mucosae is but a thin layer compared to that of 
the stomach, and is formed of smooth fibres. The submucosa is very 
much supplied with fissure-like cavities which are part of the larger 
lymph vessels. Frequently these and the mucosa to the height of the 
fold are closely beset with lymph corpuscles, so much so as to obscure 
the fibrillar character of the tissues. They frequently are more numer- 
ous, approximating to patches, but with no definite limit at certain 
points, at the base of the cylinder cells in the height of a villus. 
‘They are probably the analogues of Peyer’s glands which appear to 
be absent in fishes, although the sturgeon has in the mucosa of its 
spiral valve a number of closed spherical cavities surrounded by a 
sheath of dense adenoid tissue and filled by a great quantity of 
corpuscles. These, I would say, are the nearest, probably the only, 
‘approach to a likeness of Peyer’s glands in fishes. 
The surface of the membrane is increased by deep erypts which 
are lined with an epithelium like that of the general surface. These 
‘crypts are never branched, being simply straight tubules. They 
represent in fishes the Lieberktihnian glands of higher vertebrates, 
although the epithelium constituting them is not differentiated. 
The epithelium consists of long cylinder cells, among which are 
found modifications of them in the form of beaker cells. The eylin- 
der cel] is of equal diameter in its upper two-thirds, and has a fine 
basal process running into the tissue of the mucosa. I have never 
succeeded in isolating it to its fullest extent. As far as it has been 
‘separated it was observed to be varicose in its course and frequently 
branched. The situation of the large oval nucleus is various, and 
-when a section is viewed several layers or stratitications of nuclei 
‘are observed. Nucleolar bodies may be present in the nuclei. In 
the protoplasm of the upper half of the cell are a quantity of 
granules, fine and coarse, the latter abounding, and after food has 
been in the midgut for some time, fat globules. These diminish in 
‘quantity towards the nucleus. In transverse section these cells 
appear hexagonal in outline. The peripheral wall is quite thick, 
