Birge—Notes on Cladocera. 
1031 
fera show a distinct though small inequality in the length of 
the setae, instead of. the uniformity shown in the figures of 
iSars and Lilljeborg. 
The feet closely resemble those of L. setifera except that the 
sixth pair has the branchial sac. 
The intestine is remarkable for having a pair of large 
hepatic coeca, which extend ventrally from the point of at¬ 
tachment to the intestine toward the place of insertion of the 
antennule. When seen from the side they conceal the middle 
part of the brain. It appears that this position is accommodated 
to the very large antennary muscles and perhaps gives us a 
hint that the development of these muscles in the Sididae is 
the cause of the absence of the coeca in the rest of the family. 
L. parviremis is the only member of the Sididae that possesses 
these organs. The shell gland (PI. LXVIII, fig. 5) closely re¬ 
sembles that of L. setifera; having a dorsal and a ventral loop 
but hardly a trace of the posterior loop. The eye is oval, as 
seen from the side, with numerous lenses, set at top of the 
head, and with a long optic nerve; the macula nigra is small, 
oval. The heart is elongated, like that of L. setifera. 
The male in general resembles the young female. The an¬ 
tennule (PI. LXIX, fig. 2) has the form of that structure in 
the male Latonopsis. It is very long; the base and the long 
•curved flagellum are firmly united; the distal half of the 
flagellum has a row of short, fine setae; the olfactory setae are 
borne on the side of the basal part. There is an appendix 
ciliata as in L. setifera; this is long, slender, and plumose or 
ciliate. In this respect it is unlike the smooth projection 
which occupies a similar jtlace on the antennule of Latonopsis. 
The first foot resembles that of the female, having no hook 
or other clasping organ. There are two simple, cylindrical, 
•copulatory organs. 
L. parviremis is widely distributed in northern Wisconsin 
and Michigan, having been found in numerous lakes and 
ponds of that region. I found it first in 1897 in a small pond 
on the shore of Lake Superior, and it has constantly appeared 
in collections made since that time. It has never been seen 
from the central and southern part of Wisconsin, or in collec- 
