292 Chromosomes in the Spermatogenesis of Anasa Tristis 
scured, but all the ten large chromosomes, without exception, show a 
secondary furrow. As far as we are aware, there is marked agreement 
among cytologists in their interpretation of the significance of the second- 
ary furrow of the anaphase stage, and if this secondary furrow must be 
interpreted for some of the chromosomes as foreshadowing the plane of 
the second division, we certainly have a right to include the eccentric 
in this interpretation, and we claim for these cases in which the second- 
ary furrow is not obscured, the weight due positive evidence as opposed 
to negative. 
We have now reached a stage in the development of the eccentric 
chromosome to which we would give special attention. Previous investi- 
gators of the spermatogenesis of Anasa tristis have either overlooked or 
ignored the occurrence in the first spindle of a phenomenon which they 
have, however, observed in the second spindle and have interpreted as 
proving that one of the chromosomes of the second spindle passes undi- 
vided to one of the daughter cells. Wilson’s demonstration of this phe- 
nomenon in the second spindle is shown in Text Fig. 2, m and n. Al- 
though each of these sections shows only five of the eleven chromosomes, 
he demonstrates between the poles of each spindle one chromosome as yet 
undivided. Text Fig. 1 (160 and 161) shows two of Montgomery’s 
figures, illustrating this same phenomenon and Text Fig. 3, one of Paul- 
mier’s sections of about the same stage as Wilson’s preparations m and n, 
shown in Text Fig. 2. A comparison of these figures with our photo- 
graphs of the second spindle (34 to 42, Plate IIT) will demonstrate that 
these photographs and the sketches above mentioned represent the same 
phenomenon. This undivided chromosome so often seen between the 
poles of the second spindle we interpret as a chromosome merely retarded 
in division and believe that normally it finally divides. We cannot, there- 
fore, accept the conclusion of Wilson and Montgomery that this chromo- 
some normally passes undivided to one pole of the spindle. As men- 
tioned above, we have been able to demonstrate that a like phenomenon 
may occur in the first spindle, where the fact of the final division of the 
lagging chromosome cannot be questioned, and we believe we must inter- 
pret the second spindle in the light of the first. 
Plate III, Photos. 1 to 18 inclusive, demonstrate the presence of a 
lagging chromosome in the first spindle. We interpret this lagging 
chromosome as the eccentric chromosome of the earher stages, and this 
interpretation is based on the fact of its typical position outside the 
circle of nine chromosomes. The force of this evidence will be appre- 
ciated by comparing Photos. 12, 13, 16, and 18, Plate II, with Photos. 
