180 J. T. CUNNINGHAM. 
nature of the follicular epithelium lining the wall of the 
spermatic capsules, the other is the origin of the capsules. 
The two points are so closely connected as to form a single 
question. I have figured the appearance of the follicular epi- 
thelium as seen on opposite sides of a partition between two 
capsules in Pl. IV, fig. 13. The outlines of the cells in my 
preparations are not distinct, the nuclei are considerably smaller 
than those of the spermatocytes, and vacuolar in appearance ; 
they contain little chromatin. These cells, in my preparations 
at least, and in Nansen’s figures also, are irregularly arranged. 
Some of the nuclei are constricted, and some divided into two, 
as though they multiplied by direct division. I agree with 
Nansen in thinking that they have nothing to do with the 
formation of spermatozoa. It seems to me very probable that 
their function is to supply nutriment to the growing and multi- 
plying spermatoblasts, and perhaps they perform this function 
by proliferation and actual dissolution. 
Figs. 14 and 15 are from sections of very young undeveloped 
testes; they show the proliferating genital tissue, which in 
other Vertebrates has been described as germinal epithelium. 
The structure of this tissue corresponds almost exactly to the 
germinal epithelium in Teleostean fishes as described by 
Hector Jungersen. It is proliferating tissue, the cells being 
naked at the surface, and without regular arrangement ; that 
is to say, they do not form a definite epithelium. In this tissue 
it is easy to distinguish two kinds of cells—a large number of 
small, and a few much larger scattered at intervals among the 
others. The smaller cells are stroma-cells (s.c.),and resemble 
ordinary embryonic mesoblast-cells, as in fact they are. The 
larger cells (g. c.) are primitive germ-cells, and do not differ 
in any way from the primitive germ-cells, or, as they are often 
called, primitive ova, of Teleostean embryos. As the tissue 
increases in bulk the inner portion of it forms testicular cap- 
sules, of which several in different stages of development are 
seen in the figures. In many cases a single germ-cell is seen 
surrounded by stroma-cells. The stroma-cells afterwards form 
the follicular epithelium of a spermatic capsule, while the multi- 
