The Food of the Smaller Fresh - Water Fishes. 
71 
troduction to the Study of Fishes.” Although our genera both 
belong to the carnivorous section, it will be seen that they are not 
by any means strictly confined to animal food, vegetation mak- 
ing about one-fifth of their usual nutriment. 
Fundulus diaphanus, LeS. Barred Killifish. 
This species is very abundant in the northern part of the State, 
especially in lakes or in clear and sandy streams, but we have not 
taken it anywhere in Central or Southern Illinois. Most of our 
collections were made in the lakes of Lake and McHenry Coun- 
ties. 
The intestine is shorter than the body, the gill-rakers are short, 
obtuse, and few in number, the pharyngeal jaws are of the pave- 
ment type, set with fine, sharp teeth, and the mouth is small, but 
extraordinarily protractile. 
Eight specimens were studied, from Crystal and Cedar Lakes. 
About four-fifths of the food consisted of animal substances, the 
remaining fifth of vegetation. Except a few filamentous Algae 
taken by one of the specimens, the latter consisted wholly 
of seeds of various plants fallen into the water. Eighty per cent, 
of the food of two of the specimens, and twenty per cent, of that 
of a third consisted of such seeds; ratios evidently too large to have 
been taken accidentally. Two of the specimens had eaten Plan- 
orbis, and all had eaten insects, which made about forty per cent, 
of the food; terrestrial species, including spiders, making twelve 
per cent. Among the aquatic forms were Chironomus larvae, Hy- 
drophilidm, and larvae of Ephemeridae, the latter eleven per cent. 
Crustacea were a fifth of the food, chiefly the abundant amphipod, 
Allorchestes dentata. Cypris and Candona were likewise noticed 
in considerable quantity (seven per cent.), and a few specimens of 
various Cladocera occurred. 
Zygonectes notatus, Raf. Top Minnow. 
This species ranges in ponds and sluggish streams throughout 
the State, but is most abundant southwards. Here it may com- 
monly be seen swimming slowly about in stagnant pools, with the 
head at the surface of the water, as if interested in the phenomena 
of the weather, or possibly watching for the appearance of terres- 
trial insects. The alimentary structures are in all respects similar 
