CYTOPLASMIC INCLUSIONS OF THE GERM-CELLS. 427 
This process sometimes goes no further than in PI. 23, fig. 13. 
When this preliminary formation of a horn-like figure has 
taken place, one end, almost always the broader, undergoes a 
change. The mitochondrial bodies at this region flow 
together, as shown in PI. 25, fig. 35, forming at first elon- 
gated structures, then loops, and finally filaments, the latter 
joining up gradually to form a tangled anastomosing figure 
(PI. 25, figs .35, 36, 37, 38; and PI. 23, figs. 14, 15, and 16). 
At X.X. in PI. 23, figs. 14 and 15, the mitochondria are still 
beadlike, just as in PI. 25, fig. 36 X. In Text-fig. 2 I have 
drawn a schematic plan of the manner in which I believe 
these occurrences take place. The sum total of a number of 
involved changes is the formation of a perfectly coiled 
spireme (PI. 23, fig. 17 ; PL 24, fig. 23; and PI. 25, figs. 39, 
40, 41, and 42). In Text-fig. 2 this process is seen to fall 
under three stages: the first is the preparatory clumping 
together of the mitochondrial bodies ; the second, the 
initiation of a flowing together to form loops ; and the third, 
the joining up of these loops to form a spireme. The most 
important point to observe is that the spireme is formed 
from the chromophile rim (outer layer) of the mitochondrial 
body, while the substance, in which the spireme lies, is the 
coalesced inner substance (chromophobe part) of the mito- 
chondrial layer. In Text-fig. 2, 1-3 this is shown taking 
place. The macromitosome so formed is drawn in PI. 23, 
fig. 17 ; PI. 24, fig. 23 ; and PI. 25, figs. 39, 40, 41, and 42 ; it 
consists of two parts, the inner chromophobe cores now com- 
pletely run together, and the contained spireme, or true 
mitochoudrial matter, derived from the outer chromophile 
part of the body. 
The coil so formed is of a slightly different appearance and 
size in different moths. If the diameter of the spermatid 
nucleus in a number of species be taken as 1, the ratios of 
the nucleus to the macromitosome in these species is as 
follows : 
