ON THE SPERMATOGENESIS OF THE SILK-WORM. I3I 
We have also met with a similar large cell in the testes of 
the wild silk-worm (fig. 16), Papilio xuthus L. (fig 15), P. mach¬ 
aon, L., P. alcinous, Klug., but not in Antherea yamamai, Guér. 
Mén., Caligura. japonica, Moore., Rhodia fugax, Butl., etc. So 
it seems evident that in the genital glands of Lepidoptera, such 
a cell connecting the younger genital elements with the follicular 
wall, although not constant, is not of rare occurrence. 
I. The Formative Stage. The genital cells of this stage or the 
primary germ-cells, are situated near the blind end of each tes¬ 
ticular follicle and are arranged concentrically round the sup¬ 
porting cell as already mentioned (figs. 7, 11). The youngest 
primary germ-cells are round with distinct chromosomes and 
nucleolus (fig. 4). When the supporting cell enters the testicular 
follicle and becomes connected with the genital cells, the latter 
assume a conical shape (figs. 11, 18), the apices of which are 
connected with the protoplasmic processes of the supporting cell. 
The nucleus of these germ-cells is always situated at the basal 
part of the cell, corresponding exactly to the young genital 
cells of Pyrrhocoris apterus described by Henking (15). In each 
follicle are seen many generations of the primary germ-cells 
showing the various stages of typical karyokinesis. In figs. 17-22 
are represented various stages of division of primary germ-cells. 
Fig. 17 and 18 show cells in the resting stage; their nuclei 
present a spherical shape with a distinct nuclear wall. 
Chromatins are scattered in fine reticulum. Nucleolus is 
clearly to be seen in the centre of the nucleus. In a pre¬ 
paration fixed by the Flemming’s strong chrom-osmium acetic 
acid solution and stained by Hermann’s safranin-gentiana-orange 
the nucleolus is found to be suspended in the chromatin-net 
as one or two globules, and consists of small round chro¬ 
matic bodies. 
In the nucleus represented by fig. 17, is seen only a 
single nucleolus in the matrix of which small round granules 
are clearly to be seen, while in other cells (fig. 18), the 
(1) Cholodkowsky’s ( 6 ) observation on the testis of a Diptera, also confirms 
the presence of such a large cell in the follicle, but it seems to be of an entirely 
different nature from that of the silk-worm, as it divides mitotically. 
