On the Diinegalous Speim and Chromosomal Variation of Euschistus, etc. 127 
lymph and not in inass of chroniatin. In this object the chromatin mas.s 
does not vary with the size of the cell. The chromosomes in all six folli- 
cles agree in nnmber, volume, mode of conjngation and division, and 
therefore cannot be the cause of the dimegaly. A large spermatocyte 
of follicle 1 or 3 is several times the volume of a small one of follicle 2, 
yet no appreciable size differences of the chromosomes of the two can 
be foimd. 
It is curious that with this constancy of chroniatin mass from the 
spermatocytes up into the spermatids the sperm heads should differ so 
much in volume. But suitable staining shows that the sperm head pos- 
sesses a hollow peripheral cylinder of chromatin, not a solid rod of it. 
It is then probable that the size of the sperm head depends upon the 
amount of the karyolymph in it, and this amount will determine whether 
she sperm head be short or long. The mass of chroniatin is probably the 
tarne in both large and small spermatids, for it is not probable that the 
mass of this substance should change during the histogenesis of the Sper- 
matozoon. Therefore it is probable that the large sperm possess no niore 
chromatin than do the small, though the heads in the fornier are much 
1 arger. 
The dimegaly expresses itself accordingly in difference of amount 
of karyolymph, and of the substance (linin) that composes the mantle 
fibres, but much more markedly in amount of cytoplasm. There is a 
substance that varies in amount directly with the size of the cell quite as 
much as the cytoplasm does, and that is the mitochondrial substance. 
At the commencement of the growth period there lies at a particular pole 
of the niicleus a body (i, fig. 37) which is at this stage of eqiial volume 
in cells of all the folliclcs. Just what this body is from the morphological 
Standpoint 1 wish to leave for later decision; but it seens to be an idio- 
zome (Xebenkern) within and aroiind which mitochondria (seemingly of 
niiclear origin) appear. For present piirposes we will speak of it as the 
mitochondriuni. This mass increases directly with the amount of the 
cytoplasm: in the largest spermatocytes it is kargest (i, fig. 17), conside- 
rably smaller in the smaller spermatocytes (figs. 9, 27). In the early 
spermatids it is a much karger mass in the larger cells (t, fig. 6) than in 
the smaller cells {i, fig. 13). 
There is no evidence in any part of the spermatogenesis that 
ceUs cut off any of their substance. There is also no evidence that 
in any of the follicles the spermatozoa degenerate, therefore all niay be 
functional. 
