500 Wisconsin Academy of Sciences, Arts, and Letters. 
were empty for about the posterior third of their length and none 
contained any fully formed eggs. Near the posterior end of the 
third abdominal segment the tubules of each ovary unite to form 
the oviduct, each tubule, just before its union with the others, 
forming a loop or bend. The two oviducts gradually converge 
and meet at the posterior end of the fourth segment where they 
join and form the larger common oviduct which extends back¬ 
ward to the end of the body. Within the fifth segment and 
generally to the right of the oviduct is a partially coiled tubular 
gland which empties ventrally into the oviduct near its end. 
Each ovarian tubule shows that, anterior to the nutritive cham¬ 
ber there is a long terminal filament passing forward into the 
thorax and attached to the muscles in the mesothoracic segment. 
Korschelt (4) has described the minute structure of the ovary of 
Ranantra linearis, and we will give but a brief description of our 
species. The nutritive chamber (PL XXXVI, Fig. 25) excepting 
a small space near the proximal end is filled with a mass of cells. 
These are smallest at the terminal end, they gradually increase 
in size towards the basal end, and within a short distance of the 
first egg chamber several very large cells are noticed, each one 
undoubtedly destined to become an egg. The arrangement of the 
cells in a definite epithelial layer was noticeable only near the 
basal end. Xear the center of the basal end there is a granular 
mass which has a number of processes extending towards each 
end of the egg. Those towards the anterior part become lost in 
the cell mass, but those going in the opposite direction form the 
nutritive tubes, each one of which passes to an egg-chamber. 
The nutritive chamber is quite similar to that described by 
Gross (3) for asopns bidens. The first of the egg chambers is 
very small but they gradually increase in size. Besides the fol¬ 
licular layer surrounding'the string of egg chambers, there are 
two thin layers surrounding each tubule. The gland passing 
into the oviduct is very narrow. Its wall (PI. XXXVI, Fig. 26) 
consists of an external layer of longitudinal muscles and con¬ 
nective tissue and an internal layer of epithelial cells. These 
are of two kinds, differing apparently only in their thickness. 
Xear the free edge of the cells there is a peculiar serrated ap¬ 
pearance showing a lighter margin into which processes of the 
more deeply stained protoplasm protude. 
Within the prothorax there are a number of muscles which 
are very noticeable when this part of the body is opened. (PL 
