AVIAN CESTODES. 875 
front of that first of all treated of in the present account of the 
development of the uterus of Rhabdometra. Here the connection 
of the paruterine organ with the uterus happens to be plainly 
visible in one seouion. and, therefore, to be more striking and 
less liable to doubt than when it has to be followed out from 
section to section. Furthermore, in subsequent sections, where 
the uterus is more advanced and lies also in front of the vas 
deferens, the tissue of the paruterine organ is seen to pass 
continuously into that of the uterus, and the nuclei of the walls 
of both appear to be identical. 
These facts—that is to say if it be agreed that they prove a 
connection between the paruterine organ and the uterus—enable 
us to get over certain morphological difficulties relating to the 
homologies of the uterus and paruterine organs of some other 
Tapeworms. 
In describing the structure of Znermicapsifer capensis* I had 
to refer to an important difference in the uterus of this form as 
compared with other species referred by v. Janickif to that 
genus (his own). Briefly put, the difference is this: in J. capensis 
there was no continuous uterus, but only a series of detached 
cavities which appeared to be formed independently in the 
medullary parenchyma. These cavities were formed subsequently 
to the extrusion of the ova from the ovary and their scattering 
through the parenchyma of the medulla. Furthermore, there 
was also to be observed, and again unconnected with the ova at 
first, a condensation of the medullary nuclei to form a kind of 
network pervading the medulla. This network was often to be 
observed in re‘ation to the ova £. 
Out of this dense tissue, which ultimately surrounds the ova, is 
formed the series of paruterine organs which characterise this, as 
well as a few other genera of tapeworms (Davainea, Thysanotenia). 
T held that the network of parenchymal tissue, out of which the 
paruterine organs were formed, and the cavities in which lay the 
egos singly or in groups, were not the equivalents of the branched 
uterus described by v. Janicki in an allied form, /nermicapsifer 
hyracis (which I removed to the genus Zschokkeella), because, if it 
were, it would be a subsequent stage due to the obliteration of the 
pre-existing cavity; and as the ova appeared in it later it could not 
be a subsequent stage. I believe that the matter becomes clear 
through the-observations which I have recorded in the present 
paper. . We have in RLhabdometra, as in Inermicapsifer, a conden- 
sation of nuclei to form structures or cavities to contain the eggs. 
In Rhabdometra there is one extensive condensation of the kind 
to form the paruterine organ and a delicate strand which extends 
through part of the rest of the medullary parenchyma and would 
appear to be the seat of the formation of the uterus. In my 
species of Znermicapsifer there is the same condensation of the 
* P.Z.S. 1912, p. 588, etc. 
+ Jen. Denkschr. xvi. 1910. 
t Beddard, loc. cit. text-fig. 67, p. 583. 
Proc. Zoou. Soc.—1914, No. LIX. 09 
