294 Chromosomes in the Spermatogenesis of Anasa Tristis 
the right pole shows the complete number, eleven chromosomes, while 
at the left pole there are only ten, indicating that the lagging chromo- 
some in this instance divided as we see demonstrated in Photos. 4, 8, 
and 9. 
Although the chromosomes of these preparations show marked varia- 
tion in size their identification as the chromosomes of the first division 
is assured by comparing them with similar stages of the second spindle, 
Photos. 26 to 46. In addition to the size relations the difference in the 
form of the chromosomes at the telophase of the two divisions is often an 
aid in identification, the chromosomes at the telophase of the first 
division, as a rule, showing a more or less complete dyad form, fore- 
shadowing their second division. For example, the chromosomes of 
Photo. 10 are not much larger than those of 33, but all the chromosomes 
of Photo. 10 (except the microchromosomes) show the dyad form. 
Photos. 2 and 3 show the eccentric chromosome only slightly retarded 
in its division, but in Photo. 4 the retarded condition is more pro- 
nounced. In this photograph all the eleven chromosomes are in evidence 
and those forming the typical circle at each pole show without exception 
the dyad form, the constriction which in other niaterial is interpreted as 
forecasting a second division. It is most significant that in addition 
to these dyads one of the daughter eccentric chromosomes,—the one most 
remote from the pole to which it is destined,—also shows the dyad form, 
and we interpret this as having the same significance as the dyad form 
in the other chromosomes. 
Photo. 5 shows two first spermatocytes at the same stage (telophase) 
as Photos. 2, 3, and 4. The chromosomes of the two cells have just 
divided forming a group of four second spermatocytes. At each of the 
four poles we find a lagging chromosome again unmistakably the eccen- 
tric. The point in this preparation to which we wish to draw attention 
is the fact that the attenuated condition of this eccentric chromosome— 
due perhaps partly to the technique—has accentuated the secondary fur- 
row. We have in this preparation a somewhat exaggerated illustration 
of the typical secondary furrow which can be seen in the same chromo- 
some of Photos. 4, 10, 13, 14, 15, 16, 18, 19, 20, 21, and 22—this furrow 
we interpret as indicating a second division for this chromosome. 
Photos. 6 and 7 represent a little earlier stage than Photo. 5. The 
lagging chromosome of the first spindle is here shown in a position very 
characteristic of the lagging chromosome of the second spindle. For 
example, compare these photographs with Photos. 33 to 40 of the second 
spindle. The dyad character of the chromosomes of Photos. 6 and 7 is 
