902 W. BLAXLAND BENHAM, 
In fig. 22 I have drawn a section along the penis, in order to 
show the character of the cells which give rise to the chitinous 
penial sheath, and their continuity with neighbouring epithelia. 
The figure is sufficiently explained, and confirms the drawing 
(fig. 21) which is made from a living specimen, but where 
of course only the cuticular structures (except the penis itself) 
are shown. 
The Female Organs.—There is a pair of ovaries in Seg- 
ment x1, usually concealed in a fully developed individual by 
other structures. 
As is the case in other Oligocheta, eggs leave the ovary 
and undergo further development in an “ovisac;” this in 
Heterocheta occupies Segments x11, xiv, and sometimes 
xv. Usually this sac contains two or three very large ova, 
one in each segment; there is a contractile vessel in the wall 
of the ovisac, as in the case of sperm-sacs. 
The oviduct is a small funnel opening externally between 
X1/XII. 
As in other members of the family, there is a pair of 
spermathece in Segment x. Each spermatheca consists of a 
short, narrow duct, and an elongated, wide, tubular sac. The 
duct is shorter and the sac longer than in most other genera, 
the duct being about the same size as in Limnodrilus 
Udekemianus, Claparéde. The pore lis in a line with the 
spermiducal pore, and, like it, has the cuticle invaginated 
around it. 
The sac of the spermatheca may be entirely confined to 
Somite x, or may extend into the neighbouring segment. In 
the specimen from which the figure is taken the spermatheca 
of the right side is wholly in Segment x; that of the left side 
had pushed its way into the succeeding somite. In other 
specimens I have seen the sac of one side extending into 
Somite 1x, that of the other into Somite x1. 
The spermatheca, though not externally divisible into very 
marked regions beyond duct and sac, shows internally 
certain peculiar cells near the pore (cf. Vejdovsky’s picture 
of Tubifex, Pl. IX, fig. 17). The greater part of the sper- 
