760 THOS. H. MONTGOMERY, JR. 
B. The minute chromosomes 
This non-committal term is given provisionally to these cor- 
puscles. . 
In the rest stage of both generations of the spermatogonia the 
nucleus contains two minute dense bodies of different volume 
(m, figs. 1 and 3) that stain deeply with basic stains and may 
thereby be distinguished from the plasmosome (Pl) as well as 
from the general reticulum; with Hermann’s triple stain they show 
bright red, the reticulum violet and the plasmosome brown. 
These were described by me in 1901, and then I sought to identify 
them with the idiochromosomes of the spermatocytes. But 
such identification must be considered erroneous, for both of 
these bodies are much smaller than the smaller idiochromosomes, 
as can be seen by comparing the latter (d, fig. 2) with the former - 
(m, ties 1). 
On polar views of spermatogonial spindles I have not been able 
to recognize them with certainty, nor yet during the growth 
period of the spermatocytes, probably on account of their small 
dimensions. But in the late prophases of the first maturation 
division they reappear to the number of one or two, never more 
(fig. 86, m). I have never seen more than a single one in any 
first maturation spindle; sometimes it is the larger one that is 
seen (fig. 90, m), sometimes the smaller (fig. 91, m). These come 
to lie within the chromosomal plate (figs. 88, 90-93), never out- 
side of the spindle, thus behaving like true chromosomes.!° They 
lie in the equator of the metaphase of the first division, but pass 
undivided into the second spermatocytes (fig. 96). In the second 
maturation spindle they cannot be recognized, whence we may 
conclude that they either become attached to one of the other 
chromosomes, or else come to lie outside of the spindle, in which 
case they would be indistinguishable from mitochondria; the 
former alternative is probably correct, for that was found by me 
10 Tt is an important criterion of chromosomes that they are integral parts of the 
spindles, while yolk globules, chromatoid corpuscles and mitochondria always 
lie outside of the nuclear portion of the spindle—the portion composed of the man- 
tle fibers that are directly derived from linin. 
