Katharine Foot and E. C. Strobell 295 
obscured, due, perhaps, to an abnormal condition of the chromosomes 
themselves or to the technique, but we have a large number of prepara- 
tions at a little later stage of this spindle, showing the same lack of 
detail in the eleven chromosomes at each pole. The dyad character of 
nearly all the chromosomes is obscured also in Photos. 8 and 9, but the 
chromosomes can be counted and they show the typical circular grouping 
with the microchromosomes within the circle and the eccentric outside. 
Photos. 8 and 9 show one type of the retarded division of the eccentric 
in which one daughter half lags midway between the poles. 
In Photo. 10 the chromosomes are almost diagrammatic, both in posi- 
tion and form. The eccentric les above and to the left of the largest 
chromosome of the eleven, one-half of this large chromosome projecting 
beyond the circle, but the eccentric is the only chromosome entirely out- 
side the circle. All the eleven chromosomes except the microchromo- 
some show the dyad form, the secondary furrow being demonstrated in 
the eccentric quite as clearly as in the other chromosomes. 
Photo. 11 shows a telophase of the first spindle which illustrates a later 
stage of that type of retarded division of the eccentric chromosome which 
is foreshadowed in Photos. 4, 8, and 9, these preparations showing that 
in some cases one of the daughter eccentric chromosomes is destined 
to arrive at the pole much later than its mate. The position of the 
daughter eccentric in Photo. 11 bears a suggestive resemblance to the fig- 
ures frequently offered in other forms as evidence that one chromosome 
passes over undivided to one pole. Such evidence in the second spindle 
of Anasa tristis has been given by Montgomery, 06 (Text Fig. 1, 
Fig. 161) and Paulmier, 99 (Fig. 36) and Wilson, 06 (Fig. 2b). In 
the telophase of Photo. 12, Plate III, the two daughter eccentric chromo- 
somes are more equally retarded, each arriving at the pole to which it is 
destined at about the same time. The size alone of a lagging chromosome 
is not a trustworthy guide of its value, for the lagging daughter chromo- 
some of Photo. 11 is twice as large as one of the two in Photo. 12, and yet 
the ten large dyads can be counted in the right pole of Photo. 11. 'The 
danger of determining the value of a chromosome by its size alone can be 
appreciated further by comparing, for example, the lagging chromosome 
of Photo. 29 with the lagging chromosome of Photo, 39—one is fully 
twice as large as the other, although neither has yet divided. 
Photos. 13, 14, 15, 16, 17, and 18, are first telophases showing a 
repetition of this same phenomenon, 7. e., the eccentric chromosome 
more or less isolated from the rest of the chromosome group, and in 
many of these cases its dyad form is quite as pronounced as in all the 
