292 
Birge—Notes on Cladocera. 
length and have two anterior sense-hairs. The first leg lacks 
the flagellum. 
The following differences are found: 
M rectirostris. M. propinqua. M. ctffinis. 
Ephippium, smooth iD center, smooth in center, reticulate. 
Terminal claw, pectinate, not pectinate, pectinate. 
Valve, smooth or faintly reticulate, anastomosing str.'ae, anastomosing striae- 
Antenna, smooth, villous, villous. 
Male antennule, bend close to middle, bend close to middle, bend near head. 
Terminal hooks, six, three, four. 
Zoosperm. radiate, spherical, spherical. 
In view of these differences I have decided to consider this a 
separate species. It is certainly as distinct as is M. propinqua 
and as species of far-distant countries,, are so nearly allied it- 
becomes necessary to mark every difference in order that 
students may, note the extent of variation. No doubt later re¬ 
visers of the genus will reduce the number of species. 
This species is of common occurrence in Wisconsin and has 
piobably been found elsewhere in the United States. The de¬ 
scriptions given by Herrick and others are not in sufficient 
detail to enable one to decide whether the form found was this 
or the regular M. rectirostris. 
The species occurs in muddy pools and similar localities after 
the regular custom of Moina. 
Moina elagellata, Hudendorff, variety. 
Plate X, Figs. 2, 4, 6, 9, 10, 11. 
This species appeared in a muddy pool in Madison in July, 1892, 
and in June, 1893. The specimens included males and females 
with ephippia. These specimens closely resemble the elaborate 
description given by G-ruber and Weismann for this species 
under the name of M. paradoxa (’77, pp. 82, ff). There are some 
differences which would warrant the separation of the American 
form as a distinct variety if they should be found constant in 
specimens from other localities. These are: 1. The shell is 
marked with striae, much as in M. affinis , Birge. These can be 
easily seen in clean individuals even under the coverglass. 
