SPERMIOGENESIS OF HELIX ARBUSTORUM. 
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found on examination of living cells that their chromatin gradually 
contracted when they were dying. His figure (10, PI. I., Fig. 12), as 
well as those of Davis (19, Pl. II., Figs. 24—25) really show patholo¬ 
gically changed cells. 
A careful study of the synaptocytes of H. arbustorum led me to 
the conclusion that the contraction of their chromatin is not an artifact, 
but a normal condition. I regard as an evidence of this statement the 
fact that I have got the same, or nearly the same microscopical figurés 
by all the used fixing agents, the inner figures being quite similar to 
the peripheral ones. If the contraction of chromatin were due to the 
shrinking influence of the reagentia, then it would be quite obscure why 
are not the neighbouring cells shrunken which are at an other stage of 
development? It is undoubtedly true that the chromatin of these cells 
which have a tendency to contract themselves, can be more easely 
influenced by the reagents, and I myself have sometimes found in my 
preparations made with Perényi’s fluid, cells the chromatin of which 
was contracted into an unformed mass, but such cells were always well 
distinguishable from the synaptic ones, the latter having separated threads. 
The chromatin of the synaptocytes first forms itself into thin 
threads, such a nucleus is called after Winiwarter (128) leptotene 
nucleus (PL VIL, Fig. 12.). The threads in the next stage transform 
themselves into thicker ones (PI. I., Fig. 13., pachytene nucleus, Wini¬ 
warter), and they occupy also one side of the nucleus. The transfor¬ 
mation of the leptotene spireme into the pachytene one takes place very 
suddenly which can be concluded from the fact that no transitions are 
to be found between them. The same observation was made by Lérat (61) 
in Cyclops strenuus , the leptotene spireme of which transformed itself 
by leaps into pachytene spireme. 
During this early growth period the chromosomes assume the form 
of polar loops, as is well visible on the next figure (PI. VIL, Fig. 14.), 
directed with their open ends toward a determined point (distal end) of 
the nucleus, where they are more or less closely attached to the nuclear 
membrane. Their number is appearently reduced. Together with the 
formation of the loops the amount of the cytoplasm increases, and the 
nucleolus also becomes larger which lies then, as a rule, near the open 
ends of the loops. This was named bouquet by the French authors. 
Such an arrangement regularly occurs during synapsis in the germ-cells 
of many animals. Davis (19) has given a nearly complete list of them, 
therefore I can renounce doing so. 
Near the open ends of the loops in the cytoplasm lies a particular 
cell-organ which was discovered by la Valette St. George in 1867. 
