610 Wisconsin Academy of Sciences, Arts, and Letters . 
The ganglion is large and saccate; the only remnant of the 
retrocerebral organ is a minute sac behind the eye-spot; it is 
rendered semi-opaque by included bacteroids. 
Total length 200-225/a ; toes 17-20/a ; trophi 13/a. 
Proalinopsis caudatus is fairly common in weedy ponds, but 
readily escapes observation on account of its excessive transpa¬ 
rency. It is easily distinguishes from other Notommatids by the 
small corona, gibbous abdomen, and the unusual form of the foot. 
The setigerous papilla on the anterior foot joint probably cor¬ 
responds to one frequently found on the terminal foot joint at 
the base of the toes; it is, however, more prominent than in 
other species. The toes are always carried closely appressed and 
have never been seen to separate; whether they are really immov¬ 
able is not known. 
BIRGEA Barring and Myers, new genus 
Birgea enantia Harring and Myers, new species 
Plate LVIII, figures 1-4 ' 
The body of this species is short, broad, and truncate ante¬ 
riorly; the width is one third of the length of the body proper. 
The integument is flexible, but the outline is fairly constant. 
No transverse folds are present to indicate the limits of the 
head and neck. The head is very broad, as wide as the widest 
part of the abdomen. The neck is represented by a slight con¬ 
striction behind the dorsal antenna, about three fourths the width 
of the head. The abdomen is ovate in outline and somewhat ab¬ 
ruptly reduced posteriorly to a short, bulky tail. The foot is ex¬ 
tremely slender, and its length is one fourth of the length of the 
body; it has three joints, of which the posterior equals in length 
the two anterior joints. The toes are moderately long and 
lanceolate, ending in long, acute points; their length is one tenth 
of the total length. 
The dorsal antenna is a very large, knob-like projection at 
the base of the head with a small tuft of setae at the center; 
the lateral antennae are very slender and relatively long tubules 
with a few very long setae. 
The corona is frontal and has a circumapical band of short 
cilia, interrupted dorsally and passing in a curve to lateral, au- 
