THE GIANT EARTH-WORM OF GIPPSLAND. 29 
extra length and the special bridge of muscle may be contrivances to allow of the 
sudden expansion and contraction of the great muscular septa in this part of the body, 
without hurt to the vas deferens. In the body wall the duct runs directly backwards 
(Figs. 3 and 4, vd.,' vd.’ and Fig. 30, vd.) The second opening and vas deferens have 
precisely the same relationship to the septum as the first ; and the two vasa deferentia 
in passing backwards lie close together, the second immediately above the first. This 
relationship is retained (Fig. 30) until the prostate gland (pr.) is reached. Through- 
out the entire course each tube contains, in its circumference, some eight cubical 
cells, never more apparently, and is always richly ciliate the whole length. In the 
eighteenth segment the two ducts run upwards within the connective tissue of the 
prostate gland, and then turning downwards again (Fig. 30) follow the course of the 
duct leading to the exterior, running through the strong circular and longitudinal 
muscles surrounding the opening of the prostate, until they enter side by side. The 
cilia stop exactly where the ducts enter the prostate. 
The Prostate Gland (Figs. 3 and 4, pr.) is, as said before, a large coiled mass on 
either side in the eighteenth segment. What its function is must be regarded as 
doubtful. It may be divided in Megascolides into two distinct parts, (1) an outer 
smaller part leading to the exterior, and serving both as the opening for the gland 
and for the vasa deferentia. This has simply (Fig 30) the form of a tube lined by a 
layer of deep and distinctly nucleated columnar cells, directly continuous with the 
epidermic cells at the mouth of the gland (mo.) In its upper part this tube is much 
coiled. It is surrounded by a great development of circular and longitudinal muscle 
fibres. Possibly the straight portion of the tube into which the vasa deferentia open 
and pour their contents (vo.), and which opens on the papilla before referred to in the 
swollen part of the clitellum in the eighteenth segment, may be eversible. There is no 
trace whatever, so far as could be seen macroscopically and by means of sections, of 
any penial setee. 
2.—The second portion of the prostate, comprising almost all the coiled duct part, 
has a very different structure ; its walls are much thicker, and consist of two distinct 
layers—an inner and an outer. The inner is composed (Fig. 29, sp.’) of a single layer 
of cells, though occasionally these may be very long and extend into the second part. 
They are columnar in shape, and placed with their long axes radiating from the lumen 
of the tube (int.) Their chief peculiarity consists in the way in which they absorb 
staining material (borax carmine and hematoxylin), and hence appear in section to be 
very much darker than the outer-lying cells. The cells are, as a general rule, filled 
with a granular protoplasm, and much resemble in form those of an ordinary columnar 
epithelium, save that they are much more loosely placed together, and each has an 
internal rounded end, whilst (as represented in the figure) many of them may be 
larger than the others and extend far into the outer layer. Some of the cells have 
an empty appearance—as if they had poured their contents into the lumen—and in 
none of them can any nuclei be detected. 
