THE MEIOTIC PHENOMENA IN BLAPS 85 
somes, which still occupy one of the halves of the nucleus, it is 
very difficult to observe their actual pairmg. Moreover, since 
the X-complex arises before the leptotene threads are formed, it 
is possible that synapsis takes place also in the prochromosome 
stage. Therefore, it seemed inadvisable to recognize a definite 
synaptic stage. 
The postsynaptic stages are the following: 
f. The early pachytene stage, in which the bivalent euchromo- 
somes are confined to one of the nuclear hemispheres and produce 
a condition which could be compared to the bouquet stage in 
other animals. 
g. The pachytene stage proper, with thick and apparently un- 
divided threads scattered within the nucleus. 
h. The diplotene stage, during which the euchromosomes split 
lengthwise; this stage leads gradually to the prophase of the first 
maturation division. 
Since the behavior of the chromosomes of the X-complex differs 
from that of the euchromosomes, it has seemed advisable, for 
the sake of clearness, to consider it separately. 
A. Presynaptic stages,and synapsis. a. Resting stage. There 
is no doubt that a resting stage intervenes between the last 
spermatogonial anaphase and the prochromosome stage, for, be- 
sides the evidence furnished by the seriation of the stages, sper- 
matocytes in both conditions were found within the same cyst 
(fig. 64). 
With exception of the spermatids, the resting spermatocytes 
are the smallest cells in the testis. The chromatin appears in’ 
their nuclei as scattered masses very similar to those described 
in the spermatogonia (fig. 65); as in the latter, a deeply stained 
mass of chromatin can be detected sometimes, resembling more 
or less closely a chromosome with very ragged outline, often 
broken up into several masses. This body is the X-chromosome 
and its history could be traced to the succeeding stages. 
The condition of the chromosomes is brought about by the 
same process as in the spermatogonial anaphases. In no case 
do the chromosomes retain their dense condition, but they pass 
into the stage just described, which appears to be of rather long 
