594 
cular cells of the parenchyma it was found that at the time of testis- 
formation many of the muscle-cells in the testis-zone showed evidences 
of amitotic division and more or less extensive changes in their cyto- 
plasm. In Fig. 2 one of these cells is shown in which the nucleus 
is undergoing amitosis. The broken line indicates the space in the 
parenchymal substance originally occupied by the cell. The cytoplasm 
is in the form of irregular shreds and masses connected by strands 
and appears almost as if undergoing degeneration. In Fig. 3 one of 
these cells is shown containing one “resting” nucleus and one in mi- 
tosis. This is the only case in which mitosis has been observed at 
this stage although a most careful examination of hundreds of cases 
has been made. In Figs. 4 and 5 still later stages are shown in which 
Fig. 5. 
the nuclei have increased in number and are continuing to increase 
amitotically. In these figures the cytoplasm is seen to be concentrated 
about the nuclei, the muscle-fibre not being included in the syncytial 
mass. During this increase in the number of nuclei the cytoplasm 
seems to increase in amount and also stains much more deeply — a 
difference not clearly shown in the figures. The outline of the space 
previously occupied by the muscle-cell is still clearly visible but no 
distinct cell membranes exist. 
These syncytial masses which are without doubt derived from 
muscle cells are the early stages of some of the testes. There seems 
to be no room for doubt on this point for they are quite characteristic 
in appearance and no groups of nuclei except those developing into 
testes are found in the parenchyma at this stage. 
