CYTOLOGY OF ANISOLABIS MARITIMA BON. 
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to the other. Figures 40 and 41 represent two anaphase plates 
of a single cell, similar to that shown in figure 39, but cut through 
the equatorial zone so that one section contains one plate and the 
next section its sister. In both plates eleven of the chromosomes, 
the autosomes, are similar; and the large xx-element in figure 41 
and the smaller y-element in figure 40 occupy corresponding 
positions. 
Following the telophase of the first meiotic division there is 
a definite interkinetic period with the establishment of a well- 
defined, nuclear membrane (Plate XXVI, fig. 42). The centro- 
someof the primary spermatocyte telophase remains visible and 
establishes the spindle of the secondary spermatocytes. The 
dyads remain rather distinct, deeply staining, block-like masses 
in the nucleus of the interkinetic stage. 
With the formation of the secondary spermatocyte spindles 
we now have two distinct types of metaphase plates: those 
with twelve chromosomes, and those with thirteen (Plate XXVI, 
figs. 43-47). The twelve chromosome plates consist of 11 dyads 
and a y-chromosome. The thirteen chromosome plates consist 
of 11 dyads and two x-chromosomes, which separated from each 
other during the interkinetic period and are here represented by 
two discrete elements. Figures 46 and 47 (Plate XXVI) show 
two pairs of sister second spermatocytes, one in each pair con- 
taining twelve, and the other thirteen chromosomes. The 
former figure is taken from a section, the latter from a smear 
slide. 
Occasionally giant secondary spermatocytes are formed with 
all the chromatic elements of the first maturation spindle present, 
the chromosomes having divided but the cytoplasm having 
failed to do so. Two such metaphase plates are shown in 
figures 48 and 49 (Plate XXVI) and each has 25, well-defined 
chromosomes. 
The second maturation mitosis divides all the chromosomes 
equationally, and they pass to their respective poles without 
lagging. Figures 50 and 51 represent sister anaphase plates, 
drawn from a smear slide, and showing an exact correspondence 
in their chromatic elements. The spermatids (fig. 52) are formed 
