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APPENDIX.

ON THE CRUSTACEA EATEN BY FISHES.

I have recognized the following genera and species of Crustacea in the

stomachs of the fishes of the preceding list, several of them being new to the

state. The material afforded has been by no means exhaustively studied,

and the list of species could probably be quadrupled. I have refrained

from formal description of some species which are evidently new, preferring

to wait for specimens in more perfect condition.

Cambanis immunis, Hagen.

This is the only craw-fish I have yet noticed in the .stomachs of fishes,

and this I have seen but once (in the short-nosed gar;, unless young indi-

viduals eaten by a small cat-fish (^Amiurus melas) also belonged to this com-
monest of our species.

AUorchestes dentata, (Smith) Faxon.

Specimens of Lepiopomus paUidus, taken in Crystal Lake, McHenry
Co., in June, were feeding chiefly on this crustacean. It has also been

found in the same species, in L. ischyrus and in Morone interrupta from the

Illinois at Peoria.

Crangonyx gracilis, Smith.

The western form of this species (see Bull. No. 1, p. 6) occurs abund-
antly throughout central and southern Illinois. It is a very agile and vora-

cious creature, behaving in a jar of entomostraca like a tiger in a sheep-fold.

I have noticed that ponds in which it is at all common are nearly or quite

destitute of Euhrancliipus. The "handiness" with which it uses its anterior

feet in feeding is quite amusing. I have found it eaten only by the Top
Minnow ( Zygonectes notatus.)

Asellus intermedius, Forbes.

Eaten by Aphododerus from Union Co. A species of Asellus described

by Mr. 0. P. Hay, in the paper following this, as A. militaris, has recently

been collected in the Illinois River, and has been noted in the stomachs of



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Lepiopoynus ischyrus and Eupomotis aureus. Another form which, from its

variability, I have not yet ventured to describe as distinct from intermedium,

is very common in slow streams and fresh pools in McLean Co., especially

in early spring, and has reached me also from La Salle Co., and from Wis-
consin. Its size is equal to that of communis.^ and it differs from typical in-

termedius also in the much more robust development of all its appendages,

and in the large size of the second joint of the outer ramus of the second

genital plates of the male. The form and proportions of these genital plates

must be used with caution, however, in describing species, as they evidently

vary greatly.

Leptodora liyalina, Lilljeborg.

This extremely curious crustacean, which may be known by its peculiar,

slender form (that of a true cross, the arms of which are the swimming ap-

pendages), by its extreme transparency and by the single eye in the front

end of its cylindrical head, has hitherto been observed in this country only

by Prof. S, I, Smith, by whom a single specimen was dredged in L. Su-
perioi- in 1871. * It evidently stands between the other Cladocera and the

Phyllopoda in many respects, having no slight resemblance to a larval Eu-
hrancliipus.

It occurs in considerable numbers in Peoria Lake, a mere expansion of

the Illinois River, the depth of which does not exceed eighty feet. Speci-

mens taken in a small surface net, in June, 1 877, were lost in transit, and it

was not again seen until found in the stomachs of Folyodon, Dorosoma and
Hyodon. It is not at all certain that this is identical with the European
species, all the specimens yet studied being too imperfect to decide this point.

Exirycercus lamellatus, Muell. 1

Specimens apparently of this species appear in the stomachs of fishes

from Crystal Lake, McHenry Co., (Apeltes, Lahidesthes, Fundulus) and
also in shovel fishes from Peoria Lake. It is likewise common in ponds in

McLean Co.

Bosmino, sp. ?

This genus belongs to a section of Dapniadae {Lyncodaphnia) dis-

tinguished by the long and strong anterior antennae and by the reduced im-
portance of the posterior pair. The former are tapering, curved and cylin-

drical, ( containing in our species about 14 slightly spinulose joints, with a

tuft of bristles on the front of the third) and project from the front of the

head like a bifid beak. Occurs in myriads in food of shovel fish, in carp,

buffalo, &c., and in Lahidesthes from Crystal Lake.

Ceriodaphnia angidata, (Say) Forbes.

Very abundant in central Illinois, (McLean and Rock I. counties), but

* Invertebrate Fauna of L. Superior, p. 696.



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not hitherto reported. The following is Say's description, in Jour. Acad.

Nat. Science, Phil.. Vol. I, p. 440, 1818 :

"Z>. anr/itlata. Body viewed laterally, sub-oval, contracted before,

gibbous above near the posterior edge, beneath ventricose in the middle :

back sub-ovate, acute behind and contracted before ;
sides striate with nu-

merous minute, parallel, obliqe lines. Hind edge of the body with a prom-

inent angle in the middle, which is obtuse at tip; above the angle it is

ciliated. Antenna^, 4 filaments on the superior branch, and 5 on the in-

ferior branch ; color white or red. Length ^ of an inch. Cabinet of the

Academy. Very common in the stagnant marsh water of the forests of the

Southern States."

In the Illinois specimens the head is marked off from the body by a

dorsal indentation. The color is usually white. Found in the stomachs of

carp, buffalo, sun-fish, See. It constituted the principal part of the food of

a number of croppies taken in April, from the Illinois R. The eggs be-

neath the carapace were so numerous as to give an orange color to the

whole mass of the food at this time.

Daphnia pulex 1 L.

The species referred to by Prof. Smith, under this name,* is our com-

monest Daphnia, occurring everywhere in immense numbers. It is Qaten

by Polyodon and by many small fishes.

Daphnia galeata, Sars.

A species probably the same as that figured by Prof Smith in the paper

already cited, was found in Crystal Lake,—a shallow sheet of water about 2

miles long—and was eaten in numbers by the abundant little silversides

{Lahidesthes.')

Canthocamptus illinoisensis, Forbes.

This minute crustacean was frequently found in carp, buffalo and shovel

fishes from the Illinois R.

Diaptomus sanguineus, Forbes.

In Pomoxys nigro-maculatus. Numbers of the genus unrecognizable

as to species were observed in a variety of fishes.

Many Cydops and Cypi-is, the species of which I have not attempted to

discriminate, occurred in fishes from all waters and of a dozen families.

*Loc. cit.


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