638 The American Naturalist. [July, 
From the behavior of eggs that are entered by two or more sperms 
the author concludes that cell division does not take place without 
nuclear division. In these cases, at least, the egg divides into two, or 
into four cells or partly divides according as the asters have a nuclear 
spindle between them or not. 
‘Moreover it is not the mere presence of the nucleus that is necessary 
for cell division but the nucleus must be connected with the centrosomes. 
Visible Complexity of Protoplasm in Certain Eggs.—The 
great advances which have been made since the days when the nucleus 
of an egg was spoken of as a mere vesicle with one or more “spots” in 
it are well illustrated by the elaborate study made by the Abbé Carnoy’ 
with assistance of H. Lebrun. 
With remarkable patience, skill and trained imagination M. Carnoy 
has unraveled the complexities of structures seen in many thousands of 
sections of the eggs of certain salamanders and gained by ten years of 
labor a coherent conception of the successive changes these eggs under- 
go. The beautifully executed drawings that accompany the memoir 
show most remarkable arrangement of “ chromatin ” or staining material 
within the nucleus; the nucleus appears as a sphere of most complex 
and changeable structure—even the “ spots ” or nuclei within it having 
more complexity of structure than can be seen in many whole nuclei. 
The paper describes the appearance of the egg nucleus at successive 
stages while it is growing ripe in the ovary. Chiefly Salamandra macu- 
losa Laur. and Pleurodeles Waltlii Mich. served for material. 
In the former, fertilization takes place about the first of July ; the 
young are born alive the following Spring and leave the water towards 
September. The eggs in these young are about 200» in diameter with 
a nucleus 110% the end of the following May. The second May the 
eggs are 500-600» and the third May, 1400. Not till the end of June, 
of the following year are they ready for fertilization; then they are 
3500-37001. The eggs then require more than three years to develop 
and the females are about five years old when first ready for copulation. 
As the egg enlarges during about three years the nucleus exhibits 
the successive changes described in outline below. 
In the young ovarian eggs 30 in diameter the large nucleus (18) 
contains a conspicuous filament of chromatin, which appears as a close 
loop with no free ends. Besides this the nuclear sap is also resolvable 
into a very fine network of plastin (linin of some). This chromatic 
filament breaks up and parts of it remain as nucleoli. The nucleoli are 
thus all chromatic and not plasmatic in origin. | 
° La Cellule XII. Feb. 1, 1897, pps. 191-292, pls. 6. 
