1032 Wisconsin Academy of Sciences, Arts, and Letters . 
tions mad© south of the lake region of the states named. It 
has also been found in Maine by Mr. A. A. Doolittle. It in¬ 
habits the weedy or marshy margins of the lakes and is some¬ 
times very abundant, though usually appearing as single in¬ 
dividuals in a catch. In the autumn of 1903 I found it very 
abundant in a small opening in the edge of a marsh which 
borders part of Lake Kawaguesaga at Minocqua. In this and 
several succeeding years, it was regularly present there, and 
the males appeared in October. This particular opening was 
only a few yards in diameter, lying between small projections 
of the shore of the marsh. One could just enter it with a row¬ 
boat and move about within it. The margin was bordered 
with grass and sedge and the shallow, weedy water at the edge, 
only a few inches deep, contained very numerous specimens of 
this species; as well as many other forms usually rare, like 
Lathonura. Adjacent and apparently exactly similar openings 
in the marsh, separated from this by a few yards only, con¬ 
tained merely the species of Cladocera common in the region. 
In later years this little area has been invaded by the pickerel- 
weed ( Pontederia ) which grows abundantly at the edge 
of the water; and with the entrance of this plant and the con¬ 
sequent change of biological conditions all the unusual forms 
of Cladocera have wholly disappeared from the locality or 
become very rare. 
It is plain that this species serves to bridge the space between 
Latona and Latonopsis. The form of the antennule is that 
of Latonopsis, both in males and females. The lateral expan¬ 
sion of the antenna, so characteristic for Latona, is small in 
this species and moreover is indicated in the antennae of 
Latonopsis serricauda Sars and fasciculata Daday. The other 
characteristic Latona features are the appendix foliaceus on 
the ventral side of the head, the form of the shell gland, and 
the absence of the claspers on the first foot of the male. All 
these L. parviremis has, yet it may well be doubted whether 
it might not have been put into the genus Latonopsis had that 
genus been discovered before Latona and if Latona were still 
unknown. But there is no sufficient reason for uniting the 
two genera, as is indicated by the fact that, if this were done,. 
