446 WILLIAM M. GOLDSMITH 
As to the relation between the early spermatogonia and the 
syncytial membrane, we can only surmise. If, however, such a 
membrane does not exist prior to its apparent formation—and 
such seems to be the case—it does not seem justifiable to con- 
clude that the containing cells of each cyst were all derived from 
a single primordial germ cell. Here again, Wieman seems to 
conclude prematurely that, “‘the contents of each cyst are the 
descendants of a single mother-cell.’”’ Since the cysts were 
filled with cells when first recognized, it does not seem possible 
to determine whether or not all cells of a cyst were direct de- 
scendants of a single cell. In fact, if the membrane of the syncy- 
tium is indiscriminately formed among the early spermatogonial 
cells, as seems to be the case in the Cicindelidae, this conclusion 
cannot be justified. 
These syncytial membranes become more and more defined 
ahd persist throughout maturation. At the close of the sperma- 
togonial divisions, these membranes usually are separated at 
places by wide protoplasmic non-cellular spaces which increase 
in size throughout spermatogenesis. 
The testis of the imagos contain spermatogonial cells which are 
differentiated by neither a perceptible cell wall nor a syncytial 
membrane. Any region of such a testis may show various 
stages of cell division. Sometimes one or more neighboring cells 
in a prophase field may be in metaphase. This suggests that 
there is little relation between the adjacent cells with reference 
to their sequence of development. On the other hand, after 
the syncytial membranes are formed, it is true, as shown in 
figures 5, 6, and 7, that the stages of cellular development in 
each early syncytium are the same. This unity of cellular 
development persists until late in the maturation period. Fur- 
thermore, a cross-section of a testicular tubule usually shows as 
many distinct stages as there are syncytia represented. These 
results would suggest that the contents of each syncytium, rather 
than the cell itself, constitute a unit of cellular activity. 
