BIOLOGY. 15 
Navicula stauroptera. Stauroneis phcenicenteron. 
Navicula subinflata. Surirella apiculata. 
Navicula tenella Breb. Surirella delicatissima of Lewis. 
Navicula tuscula. Surirella (like 64 of Sch., fig. 23). 
Navicula undulata. Surirella (like saxonica, but very 
Navicula, unknown (figs. 16 and 23, pl. coarsely marked). 
III). Surirella molleriana, var. 
Navicula veneta. Surirella nobilis Grtin. 
Navicula viridis A. S. Surirella robusta Ehr. (fig. 1, pl. IL). 
Nitzschia amphioxys. Surirella splendida. 
Nitzschia apiculata. Surirella tenera Greg. 
Nitzschia communis. Surirella tenera, var. splendidula. 
Nitzschia lanceolata. Surirella tenera, var. nervosa, A. S. 
Nitzschia palea. Synedra lanceolata. 
Nitzschia paradoxa Grtin. Total genera, 14; species, 111. 
Nitzschia spectabilis. 
THE FOOD OF FISH IN CENTRAL KANSAS. 
Read before the Academy, at Topeka, December 29, 1900. 
Mr. S. G. Mead, of McPherson, gave me a smal! fish about two inches long, 
which he caught at Belvidere, Kiowa county, Kansas, last fall. It was appa- 
rently a young perch, to judge from its shape and the dark bands along its sides. 
Having a curiosity to know what its food had consisted of, I undertook a micro- 
scopical examination of the contents of the digestive tract; but the difficulty of 
arriving at satisfactory results was much increased by the carbolic acid and oil 
the fish had been preserved in, which interfered very much with the proper 
action of chemicals, especially acids, and did not seem to yield well to either 
soap, benzine, or alcohol. 
The investigation was, therefore, not altogether so satisfactory as I could 
wish; but was sufficiently so to establish the main points, and to prove that their 
food consists very largely of diatoms, mostly Navicule, of the radiosa type; of 
which I was able to make a very satisfactory examination, to be referred to again 
further on. There were also many starch grains, shown by the polariscope to be 
those of the potato, and about as many, perhaps, which were smaller, and pos- 
sibly derived from bits of bread. There were also a number of green bodies 
of roundish contour, which were without much doubt desmids. They had been 
too long subjected to the action of the gastric secretions for the species to be ex- 
actly made out, but they were probably Cosmariums of some sort; and their 
numbers were apparently too small for them to have formed a very important 
part of the fish’s diet. About a dozen grains of corn-smut were met with, all in 
one place. 
There was a very considerable quantity of white sand in the stomach and in- 
testines, hardly any field of view in the microscope one-fiftieth of an inch in di- 
ameter being without a number of grains of it. They were generally of about 
the same size as ordinary river sand, and polarized equally well. In one field of 
the size mentioned above there were thirteen grains of it, in another nine, and 
in a third five, of three taken at random. It may be possible, though hardly 
probable, that this sand was swallowed accidentally. It is, however, far more 
likely that it was swallowed designedly, to aid the process of digestion, as is the 
case with birds; and the size of these sand grains would, considering the differ- 
ence in size of the two creatures, apparently bear a just proportion to the little 
stones swallowed for this purpose by fowls. 
