CONTRIBUTIONS TO THE ANATOMY OF EARTHWORMS. 437 
an invagination of the muscular layers of the body wall to 
form the muscular coats of the spermatheca. The spermatheca 
itself (fig. 276), is lined with tall narrow epithelial cells, the 
nuclei of which are placed near the base of the cells; the 
diverticulum (fig. 27 @) is lined with an epithelium the cells of 
which are more quadrangular in shape and totally different in 
general appearance from the cells lining the pouch. In the 
sexually mature worm the character of the epithelium of the 
diverticulum alters; the cells become loaded with spherical 
refracting non-staining granules, and the nucleus, conspicuous 
through its deep staining, but deformed, is pressed close against 
the base of the cells; the epithelium at the same time becomes 
much folded so that the cavity of the diverticulum presents the 
appearance of subdivision into a series of chambers. While 
these remarkable changes have taken place in the diverticulum 
(fig. 28), the epithelium of the spermatheca is but little altered 
in character though it becomes somewhat folded. 
In Acanthodrilus Rose the structure of the spermathece 
is quite the same as in A. dissimilis; in both these worms 
the epithelium of the diverticulum does not appear to be— 
originally—so different from that of the pouch, though it 
comes ultimately to present a strikingly different appearance. 
The pouch itself is lined with tall columnar cells; in the 
interior of these are formed spherical masses of secreted 
granules which seem to closely resemble similar products 
described by Goehlich (28) in the spermathece of Lum- 
bricus; the epithelium lining the pouch is slightly folded. 
The diverticulum of A. Rose is, as I have already stated, 
composed of a relatively long tube with muscular walls which 
terminate in a swollen somewhat lobate cecal extremity 
(fig. 24) ; this latter has a structure quite like that of the 
diverticulum of A. dissimilis and of Neodrilus (see Bed- 
dard, 4). The epithelium is much folded so as to divide the 
cavity of the diverticulum ; in places the columnar character 
of the cells can be recognised, but for the most part they 
are not clearly recognisable for the reason that they have 
become largely converted into balls of a viscous-looking sub- 
VOL. XXX, PART 4,—NEW SER, F F 
