MUNSON: SPERMATOGENESIS OF PAPILIO. 
65 
The cortical nuclei .— Surrounding the grandmother cell and appar¬ 
ently imbedded in its peripheral cytoplasm are numerous nuclei of 
various sizes, mostly very minute. They extend also along the proto¬ 
plasmic projections or branches of the grandmother cell, and seem 
to surround those branches like a mantle. I have called these cortical 
nuclei. As they do not stain readily and are so variable in size 
and often very minute, they are easily overlooked, if the right kind 
of stain is not used. In this resistance to stains, they resemble the 
cytoplasm of the grandmother cell. In material prepared according 
to my method, they are made clear and prominent by means of saffra- 
nin, much less so by means of haematoxvlin. 
As the whole surface of the grandmother cell is studded with the 
protoplasmic processes or branches, these cortical nuclei become 
crowded in between the branches, making it difficult to understand 
their real nature except in very favorable cases. Out of the large 
number of these remarkable cells which I have carefully examined 
and compared, I have had several such favorable specimens from 
which my drawings are made (pi. 12, fig. 4; pi. 15, fig. 57a). They 
have shed a flood of light on the whole very complex and obscure 
problem regarding this cell colony and the origin of the primary 
spermatogones, of the gonocysts, and of the cyst cells. 
The mother branch cells .— At their termination, the protoplasmic 
strands (branches) proceeding from the grandmother stem cell, are 
connected with cells about the size of a primary spermatogone, whose 
nuclei are many times larger than these cortical nuclei. I have called 
them mother branch cells (pi. 15, fig. 57a, hr. c.). These cells are 
ovate or partly cuneate, with the nucleus located in the broad peri¬ 
pheral end and the apex turned inward toward the grandmother 
stem cell. Each protoplasmic branch (pi. 15, fig. 57a, h.) divides at 
or near its termination into several finer branches, each of which 
becomes inserted into the apex of the mother branch cell. Evidently 
the cytoplasm of the grandmother stem cell is continuous through 
the numerous protoplasmic branches with the cytoplasm of all the 
mother branch cells. Taking into consideration the great size of the 
grandmother stem cell as compared with the short diameter of the 
mother branch cell, the great numbers of The latter, thus connected, 
can be readily conceived, closely packed as they are. 
Considering the intimate relation between the grandmother stem 
cell, the mother branch cells, and the cortical nuclei, a primitive germi- 
