264 
Sidnev I. Kornhaiiser 
011 accoimt of their stainability in the growth period. There are, however, 
niany facts which argue against theii- identity with the w-chromosomes 
of Wilson: namely, 1. that there is no small compact pair of chromo- 
somes in the prophase of the first spermatocyte division; 2. that these 
chromatic nucleoli are variable in number and size; 3. are often in 
dii'ect Connection with the x-chromosome, and 4. lose their stainable 
substance in the late leptotene stage. 
The Ä-chromosome itself exhibits a variety of forms. Very often 
it is club shaped (Plate XX, Figs. 82, 86, 93—95) and contains a large 
vacuole, the chromatin being peripheral and concentrated more toward 
one end. The presence of the fluid-filled vacuole gives the a>chromosome 
the appearance when seen in optical section (Plate XX, Fig. 86) of being 
longitudinally divided. There is a clear area of cytoplasm around the 
ic-chromosome, which is not traversed by the double loops. Possibly 
there is a repulsion between the autochromatin and the a>chromosome, 
or its by-products, due to some special metabolic activity of this body. 
In the late strepsistene stage the vacuole of the a;-chromosome disappears 
and the chromatin condenses into a deeply staining rod, which is usually 
somewhat bent and may even beconie ring shaped (Plate XX, Figs. 91, 
96—100). Later this shortens and forms a deeply staining spherical 
chromosonie, while the autosomes are still tetrads of a ragged form 
(Plate XX, Fig. 101, 120). It is seen to be attached to one or more 
tetrads by linin fibers (Plate XX, Fig. 101, 120); these may possibly 
represent the former connections between the a-chromosome and 
the chromatic nucleoli which have chsappeared during the formation of 
the tetrads. 
The autosomes have been described only as far as the stage where 
the polar arrangement of the double threads (Plate XX, Figs. 82—84) 
was being lost. As this proceeds further, the interchromosonial clear 
line becomes more distinct and there appears to be an exact correspondence 
in the size and position of the chromatin granulös on either side of the 
line. Inasmuch as this was not true of the early zygotene threads, it 
must be a secondary condition. It seems improbable that the granules 
have changed position automatically, but we may find a possible mecha- 
nisni for this rearrangement in the shortening of the threads to the zy- 
gopachytene condition of synizesis — which brings the granulös into 
dose contact — and in their subsequent elongation. For, as the linin 
basis of each loop expands, those chromatin granules which are approxi- 
mated in pairs and have an affinity for each other might remain together. 
The early strepsisteile stages (Plate XX, Figs. 87, 88, 90) show the pairing 
