Gametogenesis in Cestodes. 
431 
them is open to grave doubt. The last difference mentioiied by Harman, 
namely that of length and position of the spindle is likewise open to ques- 
tion. Sueli differences may conceivably occur in the cleavage spindles 
themselves. In faet, Harman herseif shows two such spindles with one 
pole very close to the surface of the egg in her figs. F and L, pl. 4. In 
Moniezia Child’s figures of the supposedly maturation mitoses do not in 
inost cases show any noticeable eccentricity of the spindle. 
In this Connection it is interesting to note the position of the spindle 
in fig.8, pl. 11 of Child’s paper (1907, III), where it lies at right angles to 
that usually-assunied by second maturation spindles with reference to the 
Position of the first polar body. It is also of interest to note Childs State- 
ment on p. 154 of this paper that “The figures show wide Variation in the 
Orientation of the first cleavage spindle”, with reference evidently to the 
supposed polar bodies. 
I am not ready to deny that the mitoses found so frequently after 
the cggs reach the uterus are maturation and not cleavage mitoses. I 
formerly so interpreted them, and this interpretation is supported by the 
condition represented in fig. 83 of my earlier paper, which shows one of 
these mitoses in an egg in which a sperm is just entering. There is a 
possibility here however that this sperm is not entering, but is merely in 
apposition with an egg which has already been fertilized. The enlargement 
at one end of the sperm, indicates however that it is in process of fertilizing 
the egg and giving rise to a male pronucleus in so doing. But even if they 
are matiu’ation mitoses there is no sufficient evidence that they give rise 
to polar liodies, which a careful searcli of a large amount of material from 
many different species convinces me are absent. 
While the presence of polar bodies in cestodes has been assumed by 
various workers no one has yet, to my knowledge, observed their formation, 
or given any satisfactory evidence whatever of the participation of the 
maturation mitoses therein. Apart from the yolk cells, which have been 
misinterpreted as polar bodies, and which I have already discussed, there 
may often be found small granulös attached to the egg in the uterus and 
apparently resembling the polar bodies of Janicki. Fig. 1 shows some 
of these bodies in Thysanosoma actinoides. Where the eggs are so closely 
packed together as they are here it is obviously very difficult, if not im- 
possible to determine the exaet number of these attached to any egg, or 
indeed whether they are so attached at all or not. They vary somewhat 
in form, size and position with reference to the egg’s axis, and the pre- 
sence of numerous bodies identical with them, which are scattered thru 
the uterus and are apparently derived from its walls, renders their inter- 
