620 - Fresh-Water Entomostraca. - [October, 
the ascogonium is filled up by the loose tissue of the inner rami- 
fications. 7 l 
The ascogonium is divided by repeated partition into a number 
of asci, each of which in our species contains eight spores. 
According to the observations of several botanists, these spores 
are not developed before the next spring, so that the parasite is 
preserved through the winter by means of the peridia. In most 
species of Arysiphe these peridia are provided with hyaline 
appendages, some of which are of wonderful regularity and 
elegance of form, when seen under the microscope. 
:0: 
FRESH-WATER ENTOMOSTRACA. 
BY C. L. HERRICK. 
HE collector of fresh-water specimens is constantly meeting 
4 unexpected forms, especially among the smaller organisms, 
and of these no order of animals furnishes a wider variety or 
more curious adaptations than the fresh-water Crustaceans em- 
braced in the old group Entomostraca, which is by many authors 
at the present day subdivided into several orders of Crustacea, 
the name being retained for a single order. To the microscopist 
particularly they are available as a never-failing field for study, 
since a cup of water from almost any source will contain abun- 
dant material for a day’s work. | . 
The Entomostraca have specialized jaws, but the gnathites nove” 
exceed three pairs. The segments of the abdomen are devoid of 
appendages. The name was derived from two words, meaning 
insect and shell, by Otho F. Miiller, and applied by him in his 
“ Entomostraca” (1785) to the animals which had hitherto been 
all comprised in Linnzeus’ genus Monoculus, named from the sup- 
position that they possess but one eye. This order has, gener- 
ally speaking, been much neglected, and in America particularly 
it seems to have escaped attention. The members of this order 
are never large, and many are so small as to be with the er 
difficulty detected by the unassisted eye, yet from their gree 
variety, wide range and immense number they assume a position 
of considerable importance in the animal kingdom. . 
~ Recent investigations instituted by Mr. S. A. Forbes, of the 
Illinois State Laboratory of Natural History, have emphasized 
the fact that the lowly animals play important parts in the econ= 
— : Sceans enter 
= omy of nature, he having found that these Crustaceans ent | 
