34 ON THE ANATOMY OF MEGASCOLIDES AUSTRALIS, 
completely. The cocoon is very large—13-2 in. in length and 3-1 in. in breadth. 
It is leathery in consistence, rounded at either end, with a short coiled string left 
where the ends were finally closed. The cocoon corresponds to the size of the 
burrow, and each contains only one embryo. What size the embryo attains before 
leaving the cocoon I cannot say, but have found them coiled up within the cocoon, 
and reaching the length of 5-6 in. The cocoon is filled when the embryo is young 
with a milk-white fluid, corresponding to, though rather thicker than, the coelomic 
fluid, and is probably composed in part of the latter. 
The spermathece are four in number, and very large. There is one pair in the 
eiohth and one in the ninth segment. (Figs. 1, 3, and 4, 7.s.) Each one has the form 
(Plate 5, fig. 23) of a bag with a pointed extremity at its free end, and a short stalk 
for attachment to the body wall at the swollen end. Hach lies on the ventral surface 
of the body, and their ducts to the exterior pass slightly forward, so as to open just 
(Fig. 1, r.s.* 0., r,s.” 0.) within the posterior edge of the segment next in front of those 
in which they really le. A slight line on the surface of the worm encloses, as shown 
in the figure, a distinct area in which the receptacula open. No setze can be detected 
so far forward in the body of the worm I have examined, but these openings lie close 
to the segment boundaries, and would seem to have no relations to sete. They open 
at about the same distance from the median line as the ventral pair of sete, but 
quite in the posterior region of the segment. 
The receptacula are marked by very distinct grooves running longitudinally (Fig. 
23), and up each side passes a clearly-marked muscular slip (musc.) This may 
perhaps be useful in ejecting the contents of the receptacle, as on contraction the two 
slips would force the contained material to the exterior. The grooves all converge 
towards the apex, and on examining the surface carefully, circular muscle fibres can be 
detected running beneath the longitudinal ones on the exterior. At the attached end, 
and very close to the body wall, is a small diverticulum, as in other species of the 
genera described by Fiercuer, though in them (M. (Notoscolex) camdenensis and 
M. grandis) the spermathecze are much narrower and more tube-like, and in the 
former the diverticulum more prominent and further away from the external opening. 
The surface of the diverticulum in M. australis is marked by projecting coils, which 
are not well represented in the lithograph. When cut in section longitudinally, the 
structures represented in Fig. 25 are seen. Internally, the sac is lined by a layer of 
columnar epithelium, the oval nuclei of which lie close to their outer ends. Most 
externally are the longitudinal and inter-twined muscle fibres ; just within these the 
circular fibres, much fewer in number, are cut through. Between the latter and the 
epithelium is a considerable space filled with connective tissue, amongst which are 
many nuclei, whilst next to the epithelial cells is a layer formed of very numerous 
branching and interlocking blood-vessels. The great development of the blood-vessels 
in connection with the columnar epithelium cells indicates the fact that the inner 
lining of the spermatheca has a secretive function. In examining the contents of the 
