418 j. bront£ gatenby. 
mitochondrial granules which have run together to form a 
spireme ( M.D . ). 
(4) Several spherical acroblasts, 1 which soon unite to form 
the acrosome (X.X.). 
(5) A number of excretory granules (6r.). 
The acroblasts can be found easily in late stages of 
spermatocytes and in all probability are present in the sper- 
matogonium. I therefore add them to my scheme of the 
spermatogonium, only it should be understood that I could 
not find them until the spermatocyte was fairly large. The 
point which I particularly wish to emphasise is that the 
acroblasts are separate bodies in the young spermatocyte, 
and have nothing to do with the centrosome or archoplasm 
(if demonstrable). 
If the idiosome (arclioplasmic zone) of the spermatogonium 
is identical with that (acrosome) of the spermatid, we could 
only make certain of this in one way, that is, by following 
this body right up through the growth period ; by explaining' 
how the spermatogonia! centrosome needs' an arclioplasmic 
zone and the spermatid centrosome not; by describing the 
time and manner of separation of the centrosome from the 
archoplasm (idiosome) ; and, finally, by showing why some 
spermatids have several idiosome-like bodies instead of the 
regulation one. This has not been done, and I venture to 
say never will be. 
The Mitochondria. 
in the primary spermatogonium and oogonium the nucleus 
is partially enveloped by a cloud-like body, which is formed 
by a closely-massed collection of minute granules. There is 
no doubt that at this stage these granules, which are the 
mitochondria, bear some definite relation to the nucleus. 
Almost always they lie in a crescentic cloud towards one side 
of the nucleus. Whether at this period they bear a relation - 
1 Acroblast : This useful term was suggested by Dr. H. D. King, 
‘ Amer. Journ. Anat.,’ vii, 1907-8, and denotes a body which eventually 
gives rise to the acrosome. 
