41 
The general prineiple upon which the genital system of these 
animals appears to be constructed is diagrammatically represented 
in figs. 46 & 47. The duplieity of the genital glaud can, here be 
clearly made out and is especially obvious close to the anterior 
extremity, which, being less thoroughly filled with ova, remains 
divided along the middle line (fig. 47). In other regions of the 
body the walls of both halves are closely applied to each other 
when the genital products are in full development and only sepa- 
rate again posteriorly into the portions hg, hg’ which are strongly 
ciliated. These canals lead into an unpaired median cavity P (fig. 
46) from which two other paired ducts dd at the other extremity 
take their origin. After having for a short way followed a direct 
course backwards these ducts bend forwards again (d’d’), then make 
a second turn and finally communicate (00') with a pair of tubes 
AR A'R’, distinguished by the much more considerable thickness 
of their walls. Into the latter and about at the same point of 
junetion a pair of blindly ending and diversely ramified tubular 
glands EE' open. The thick-walled tubes AR A'R’ divided by 
a muscular constrietion me into an anterior (AA’) and a posterior 
(RR/) portion finally unite in the median line close to the exterior 
opening of the rectum. This short median tube (Q) then communi- 
cates (q) with ihe cavity into which the intestine similarly opens. 
Refraining for the present from any definite nomenclature of the 
parts mentioned we first have to consider more in detail the histo- 
logical characters of these different portions of the genital apparatus. 
When the animal has been cut open and the genital gland is 
exposed to view running all along the median line of the dor- 
sum, this gland is seen to be divided into a number of more or 
less regular lobes, with deep interstices between them (fig. 48). 
Sections show that the ciliated wall of the intestine folds itself 
into these interstices (fig. 51), and that it is either directly applied 
against the wall of the genital gland !), or that blood-lacunae sepa- 
1) From a few of my sections it would appear as if the contents of the 
hermaphrodite gland were occasionnally discharged into the intestinal cavity, 
in which I now and then find eggs and portions of the albuminous substance 
