Katharine Foot and E. C. Strobell 299 
43, the fibers are obscured, but the eccentric shows an indication of the 
dyad form. The presence of fibers connecting the ends of the lagging 
chromosome to opposite poles of the second spindle has been repre- 
sented by Paulmier and one of his figures showing this feature we have 
reproduced in our Text Fig. 3. His confounding this chromosome with 
one of the microchromosomes does not weaken the significance of the 
fact that this chromosome is connected with a fiber to both poles of the 
spindle. In describing the effect of these fibers on the form of this 
chromosome he says: “It is somewhat elongated as if stretched by the 
pull of the opposite spindle fibers which are attached to it,” p. 244. 
The telophase of the second spindle shown in Photo. 44 demonstrates 
that the eccentric chromosome may divide even when the poles of the 
spindle are very far apart for the daughter halves of the lagging chromo- 
some have almost completely separated. In this preparation the daughter 
cells are still attached though the constriction of the cytoplasm which 
precedes cell division has appeared between them. Probably this point 
may not be brought out in the reproductions. 
In Photos. 45 and 46 the final division of the lagging (eccentric) 
chromosome is again shown. In Photo. 46 the identity of the lagging 
chromosome is more obscure, but the fact that one of the chromosomes 
has not yet contracted as much as the others, added to its eccentric posi- 
tion, point to its identity as the lagging chromosome. This photograph 
shows also that the poles of the spindle have turned after its division— 
a feature common for both the first and second spindles. Photo. 51 
shows two resting spermatids, each with a nucleolus. 
We believe that these twenty-one preparations of anaphases and telo- 
phases of the second maturation division demonstrate that it is not safe 
to assume that because a chromosome is retarded in division it neces- 
sarily follows that it will not divide at all. It is a fact that the main 
part of the evidence that has been offered to establish the theory of the 
dimorphism of the spermatozoa is a demonstration that at the late 
anaphase or telophase of a first or second maturation division one chro- 
mosome is often found, either exactly between the poles or nearer one 
pole than the other, and in nearly, if not all, of these cases, only a few 
of the total number of chromosomes are shown. 
Examples of this kind of evidence for Anasa tristis are reproduced in 
Text Figs. 1, 2, and 3. Montgomery’s sketch 161 (Text Fig. 1) to- 
gether with the metaphase of his sketch 160 are the only figures he has 
given us in evidence of the dimorphism of the spermatozoa of Anasa 
tristis. Paulmier’s Fig. 35 (Text Fig. 3) is another example of this 
