782 Wisconsin Academy of Sciences, Arts, and Letters. 
ness in different parts. The hypodermal layer contains small 
ovoid nuclei, in it the cell boundaries are difficult to distinguish 
(fig. 56). 
The seminal vesicles lie dorsal to the union of the two 
oviducts. These (fig. 47, Rp. Sem.) are irregular in out¬ 
line and each somewhat kidney shaped; the two are joined 
together and form a body somewhat the shape of a dumb-bell. 
The union of the right and left recepticles is more clearly 
seen in a transverse section through the region of their union 
(fig. 55). In all the specimens examined the seminal re¬ 
cepticles were entirely or nearly empty and what their appear¬ 
ance would be when filled with sperm is not known. From 
the wrinkling of the inner wall one would judge that the cavity 
■would be very much enlarged if stretched by being filled. 
Median and just posterior to the union of the receptacles lies 
a peculiar chitinous piece, the collar (fig. 47, Cu. Co.). This 
at first appears to be a ring encircling in this place some part 
of the reproductive organs but a more earful examination shows 
that the ring is not a complete circle but is ventrally imper¬ 
fect. Posterior to the ring and dorsal in position there is a 
chitinous piece, not so thick as the collar, extending back and 
prolonged laterally into two blunt projections (this is shown in 
figure 47). The chitin forming this piece varies in thickness, 
being thicker near the ring than along any of the free margins. 
A sagittal section shows several muscles that arise from the pos¬ 
terior end of this piece (fig. 48, M ; ), the action of these would 
give to the ring a backward and forward motion. In this 
same view the collar has, more the shape of a wine glass, with 
these muscles coming from the tip of the stem and the cup of 
the glass being occupied by a prolongation of the cavity which 
lies just back of the junction of the receptacles. From this 
same view the chitinous piece is seen to be free on all sides 
and not connected with any other tissue; this makes possible 
what ever movement it may have. 
What this chitinous collar is for is not known and it would be 
necessary to examine a number of specimens during and after 
copulation to determine its real use. It is very possible that the 
