CALIFORNIA BUDRILIDA. 51 
Prostate (fig. 8). There is one pair of prostates of rather prominent size ex- 
tending parallel with the intersegmental groove reaching almost across the somite. 
The shape of the prostate resembles at the top somewhat a curved feather, the inner 
apex being helix-like, curving backwards. This form appears quite constant and while 
I found the length and the width of the prostate to vary, I never found one, which did 
not show the helix-like, convolution. The thickness of the prostate varies consider- 
ably. In some specimens it was almost twice as thick as in others, the increased 
thickness being caused by a gradual widening toward the inner apex. In some speci- 
mens the prostate was longer, more slender and its longitudinal sides almost parallel, 
but the convolution was generally always thickened. In most instances the convolu- 
tion could be considerably straightened out by a pushing with a needle, but it would 
when released assume its natural helix-like form. The spermduct connects with the 
muscular part of the prostate in the muscular layer of the body-wall. The sac con- 
taining the penial sets is situated immediately anterior to the prostate and somewhat 
closer to the ventral ganglion in line with the regular sete, but opens in the same pore 
with the prostate and spermduct. (Figs. 8, 51, 52, 53.) 
A eross section of the glandular part of the prostate shows that it is composed 
of two layers of cells, the outside one containing large cells of flask-like shape, the 
inner are narrower rectangular cells. The contents of both layers resemble each 
other greatly and are difficult to discern. Both layers of the prostate contain nu- 
merous blood vessels arranged like radii ina circle, penetrating both of the cellular 
layers. But the inner layer is seen to also possess a vascular system of its own with 
many smaller vessels similarly arranged. These vessels are generally wider at the 
periphery of the prostate and narrow toward the center, many if not all collecting in a 
network of capillaries spreading on the inner surface of the prostate (figs. 55 and 56). 
Otherwise these vessels do not anastomose. All these vessels are fed by a branch from 
the ventral vessel of the body, which divides on the prostate into two or three large 
branches which again fork toward the apex of the prostate in many smaller ones, as 
in Deitania Troyer (fig. 45). 
This junction of the various male organs is affected in this manner. The two 
spermducts run jointly on the top of the inner longitudinal muscular layer of the 
body-wall. When reaching the lower or muscular part of the prostate they turn and 
run parallel to it. Immediately before reaching the place where the prostate enters 
the wall, the two spermducts fuse into one duct, the lumen of which then is wider 
than the adjoining part of the prostate.. This duct joins the prostate in the iongitudi- 
nal museular layer of the body-wall. After reaching the transverse muscular layer 
this duct joins the pore of the penial setze (figs. 51, 52, 55). 
Spermatheca (fig. 13). The spermatheci consist of very minute bodies, pear- 
shaped in outline, and of extremely delicate structure, without any differentiation of 
the wall in a muscular and glandular layer. In size, the spermatheca is not much, 
if any, larger than one-half the width of the somite, when contracted in alcohol. But 
the most peculiar feature of this organ is that it is variable in number and_ position. 
