248 N. M. Srevens, 
divisions, — a transverse and a longitudinal in the spermatocyte, 
and two longitudinal divisions in the oocyte, giving, however, equi- 
valent results in the nuclei of the egg and sperm; 1. e., SE in the 
a b 
a[b 
that further investigation will show that in many if not in all cases 
the two theoretically conflicting types of maturation divisions are 
equivalent, the paired chromosomes being in all cases separated by 
one or the other of the maturation divisions. This question is of 
especial interest in connection with recent investigation of problems 
relating to Mexper’s Law of Inheritance. 
Braver’s work on Ascaris (1893) in connection with that of 
Bovert (1899) and others seems to indicate that the chromatin 
granules which Braver describes as uniting in pairs before the 
spireme is formed are the true chromosomes; and if so, one of the 
longitudinal divisions of the tetrad of Ascaris really separates paired 
chromosomes. 
Chromatin granules. — The question as to whether the 
granules thrown off by the chromosomes and cast out into the cyto- 
plasm, pass from the nucleus to the cytoplasm in the form in which 
they are seen on both sides of the nuclear membrane (p. 230—231, 
1903) is satisfactorily answered by the sections of Sagitta elegans. 
Fig. 25 shows these granules scattered through the nucleus, a few 
of them in contact with the nuclear membrane — some within, 
some without — and others in strands of karyoplasm which extend 
through the nuclear membrane out into the cytoplasm. This and 
many other similar sections show that the granules actually pass 
out of the nucleus along strands of karyoplasm. The nuclear mem- 
brane is not so definite a structure in the ripening oocytes of 
Sagitta as in many forms, though in earlier stages it is quite thick 
and is fortified on the outside by a deeply-staining reticulum which 
gradually disappears as the oocyte and the nucleus increase in size. 
With the material at hand, I am unable to give any very 
definite opinion as to the composition of these granules which are 
the product of the gradual reduction in the size of the chromosomes. 
They have been spoken of as chromatin granules, because of their 
origin, and because they stain like the chromosomes in iron- 
haematoxylin preparations and hold the stain while much larger 
yolk granules are destained. The slide from which Fig. 25 was 
sperm and in the egg and its polar bodies, it seems probable 
