980 THE AMERICAN NATURALIST. [VoL. XXXIV. 
students to the sciences of comparative anatomy, comparative embry- 
ology, cytology, general physiology, variation and inheritance, and 
the others that are grouped under ‘zoology.’ This book is like a 
‘Synoptic Room’ in the vestibule of a vast museum, containing the 
most essential things for those who can go in but a little way, but 
also fundamental for those who can penetrate farther." 
This Natural History, vivified by general physiology, seems worthy 
to replace many of the school text-books now in use, if only the 
teacher be prepared to make the field and laboratory work dominate 
over the “cram” which presentation of so many facts makes an 
opening for. 
The three hundred and eleven illustrations are a most important 
feature, remarkable in that the majority are from original photo- 
graphs. Many of these are excellent, and, as the authors state, 
* their publication may be considered as something of a contribution 
to science." Yet it is to be regretted that, in some illustrations of 
invertebrates, black photographs have been preferred to good draw- 
ings; while, on the other hand, in the higher groups, notably the 
mammals, drawings of stuffed specimens have been used, where 
photographs from life, such as those of Gambier Bolton, might have 
been used to advantage. 
We hope the book will meet with a success that will insure revi- 
sions. Meanwhile, the *blue crab" figured on page 109 will be of 
peculiar interest to the specialist. EEA 
Merogeny. — The notable work of Yves Delage, first published 
in the Comptes Rendus, October, 1898, and in detail in the Archives 
de Zoologie Experimentale, VII, Nos. 3 and 4, 1899, widens the field 
of experimental research by a new method, and adds facts difficult 
to assimilate with the current conceptions of the phenomena of 
fertilization. 
In the echinoderms Strongylocentrotus lividus and Echinus sp., in 
the mollusk Dentalium, and in the annelid Lanice conchylega, he has 
succeeded in cutting eggs into two or more pieces and in keeping 
these pieces under observation in drops of water till they developed 
into the characteristic larvae of these groups. In each case sperm 
was added, and it is inferred that it entered and fertilized the pieces. 
Moreover, in some echinoderm eggs the egg nucleus was seen in one 
piece and not in the other; yet the piece with no nucleus formed 
a larva just as well as did the piece with a nucleus. It is inferred 
that most of the fragments were without nuclei. 
