52 Tapeworm from a Parakeet 
in Monezia and Cotugnia. The only discrepancy is that the blastophore 
(“Stemmzelle”) is said to be a spermatocyte which undergoes no 
further differentiation. 
Moniez’s account (5) differs from the three preceding in that it 
asserts that the spermatocysts separate and do not fuse, each single 
cell growing and producing endogenously spermatids which in their 
turn form the spermatozoa. It also omits any mention of a blastophore. 
From the above four accounts, that of Child for Monezia, of von 
Linstow for Anomotaenia constricta, of Moniez, and of myself for Cotugnia, 
a general account of the development of spermatozoa in the Cestoda 
can be compiled. The initial spermagonium in all cases forms several 
spermatocytes, either endogenously or by continued division of its 
products. In three of the cases these spermatocysts fuse to form 
cytophores; in the fourth no fusion occurs. Again, all four accounts 
state that these cytophores divide, forming spermatids (“ Enkelzellen”), 
which in their turn produce spermatozoa. In two cases a blastophore 
is present derived from the daughter-cells (a) by growth of a single 
daughter-cell as in Anomotaenia, {h) by division of a cytophore as in 
Cotugnia. It is therefore evident that in Cestodes there is a general 
agreement with regard to the course taken by spermatogenesis in its 
broad outlines. The discrepancies, which undoubtedly exist, do not 
affect the general plan of the course taken, and may be partially 
accounted for by failure in technique and differences in the material 
used. 
Feynale Organs. 
The vagina is continuous with the extreme inner end of the genital 
cloaca (PI. VI, fig. 3). There is no sphincter muscle. After its junction 
with the cloaca, the vagina runs postero-transversely slightly towards 
the dorsal surface, bends once or twice, and then opens into the antero¬ 
lateral end of a spherical receptaculum seminis. This latter is 0-067 mm. 
in diameter, with a wall 0-0033 mm. thick, and is usually filled with a 
congested mass of spermatozoa. It lies near the dorsal surface of the 
proglottis, at about the anterior third of its length. The lumen of the 
vagina is slightly constricted as it opens into the receptaculum seminis. 
The opposite end of the receptaculum seminis opens, rather pos¬ 
teriorly, by means of a short duct into a non-ciliated oviduct (PI. VI, fig. 6; 
PL VII, fig. 19). Its ventral portion (v.ovd.), 0-0167 mm. in diameter, 
runs anteriorly and ventrally to open after a short course into the ovary. 
There is no ooclapt, a slight swelling of the oviduct at its junction with 
