176 J. T.. CUNNINGHAM. 
three or more sperm-nuclei may escape successively from a 
spermatoblast without forming more than two processes. 
In the series of sections from which fig. 12 was taken, 
although there were plenty of perfect spermatozoa, and spindles 
like those in other sections, there were several abnormal struc- 
tures like those represented at aand b. I believe these were not 
produced by imperfect preparation of the tissue, but were really 
present in this particular testis. They are obviously due to a 
coalescence or excessive enlargement of spermatocytes, the 
nuclei having segmented in the peculiar manner shown. 
Thus I think it is clear that the process of spermatogenesis 
to be deduced from the structures, seen both in fresh teased 
preparations and in stained sections of fixed and hardened 
material, is as follows:—The cells found in unripe capsules 
(Pl. IV, fig. 4) are spermatocytes which multiply by karyo- 
kinetic division. At a certain period of development these 
cells cease to divide in this way, and commence to form sperma- 
tozoa; the nucleus of the spermatocyte loses its ordinary 
structure, and the whole of its chromatin is formed into a 
number, probably six or more, of pear-shaped bodies which 
may be appropriately called sperm-nuclei. By the activity of 
the protoplasm of the spermatoblast these sperm-nuclei separate 
one by one from the latter, passing out point foremost, and 
trailing a slender thread of protoplasm behind them. The 
thread breaks near the spermatocyte, and the free portion 
then forms the tail of a perfect spermatozoon. The sperm- 
nucleus is doubtless surrounded in the head of the sperma- 
tozoon with a thin envelope of cell-plasma, which expands 
behind the nucleus into a small protoplasmic mass often called 
the body of the spermatozoon. After one spermatozoon has 
separated, another sperm-nucleus may pass out of the spermato- 
cyte along the process left behind by the former. In this way 
the remnant of the spermatocyte usually forms a spindle-shaped 
body with a process at each end, but sperm-nuclei may separate 
at three or more points instead of two, and then multipolar 
bodies are formed. 
I regret that I have not been able to trace satisfactorily the 
