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HERBERT H. BROWN. 
liberty by the disintegration of the original groups. The 
nucleus now occupies the outer part of eacli cell, i. e. that 
directed towards the wall of the tubule, and the outer part of 
each nucleus is covered only by the clear cap. At the same 
time the chromatin leaves the substance of the nucleus and 
accumulates at the nuclear membrane, and chiefly at its outer 
part which becomes thickened, while the nuclear membrane in 
other parts seems to disappear, so that the nuclei appear to be 
breaking up. It is apparently such an appearance as this, 
represented by fig. 1, c, which has led Y. Ebner and other 
observers who have investigated the spermatogenesis of the 
Rat, to the belief that these cells undergo liquefaction, and 
produce the liquid portion of the semen, or serve for the 
nutrition of the spermatozoa {vide the account of sperma- 
togenesis given by Professor Schafer in Quain’s ( Anatomy/ 
vol. ii, ninth edition), and the granules of chromatic material 
which are found between these cells and the spermatozoa, have 
been attributed to the disintegration of nuclei. The accessory 
corpuscle leaves the nucleus at this time, and becomes em- 
bedded in the protoplasm at the inner part of the cell (fig. 12, 
c ), where it remains inactive during the development of the 
spermatozoon, and is finally cast off with a residual portion of 
the protoplasm, when the process of development is nearly 
completed. 
The young spermatozoa are free in the tubule for a very 
short time only, and they now begin to form groups in con- 
nection with the supporting cells. The remainder of their 
development takes place in these groups and occupies the 
fourth and last cycle. 
The manner in which the connection between the young 
spermatozoa and the supporting cells is brought about is not 
very clear; apparently the young spermatozoa congregate 
round the processes of the supporting cells which extend 
towards the lumen of the tubule, and become embedded in the 
protoplasm, without of course any fusion between the sub- 
stance of the young spermatozoa and of the supporting cell 
taking place ; but the appearances presented by the supporting 
