No. 395.] REVIEWS OF RECENT LITERATURE. 891 
by these books has been so thoroughly worked over that any new effort 
in this direction could hardly be expected to possess great novelty and 
would naturally differ from its predecessors only in details. Emery’s 
book is conventionally divided into a general part, of some hundred 
pages, devoted to the principles of zoology, and a special part, of over 
three times this length, containing a descriptive classification of the 
animal kingdom. 
In the special part the Protozoa and Metazoa are recognized 
as primary divisions. The term radiates (zoophytes) is resurrected 
to include the sponges, ccelenterates, and ctenophors; all the 
remaining Metazoa are placed in the group Bilateralia. This in- 
cludes the worms (under which are placed the Platyhelminthes, 
worms proper, molluscoids, and Enteroptneusta), the echinoderms, 
the mollusks, the arthropods, and the chordates. The innovations 
in classification so far as they affect the larger divisions are brought 
about chiefly by the fusion of what were formerly considered sepa- 
rate groups. This seems to us to make for unnaturalness in the 
classification; thus it is very improbable, as in fact the author 
admits, that the group of worms as constituted above is a homogene- 
ous assemblage, and the division Bilateralia is in a similar way still 
less justifiable. 
The general part, Sohal. so far as it goes, is well written, natu- 
rally offers a much greater opportunity for individualizing the book. 
It is prefaced by a short hiStorical account in which the foreigner is 
struck by the translations of familiar names, such as Giovanni 
Mueller and Carlo Darwin. Then follows a brief but well-written 
chapter on protoplasm, its activities, the cell, direct and indirect 
division, etc. A brief treatment of histogenesis and organogenesis 
is followed by an account of the architecture of the metazoan body 
and a discussion of radial and bilateral symmetry, of metamerism, 
and of the laws of homologies. The significance of the individual 
and the formation of colonies are then dealt with. Reproduction is 
the title of the next chapter. Protozoan and metazoan reproduction 
are comprehensively compared, and such topics as sexual reproduc- 
tion, parthenogenesis, alternation of generations, and heredity are 
considered. The evidences and consequences of evolution conclude 
the general part. ‘This is perhaps the best chapter in the book, and 
the happy selection of Italian examples and illustrations makes it 
enjoyable reading even to the mature zodlogist. 
While the general part compares very favorably with, the corre- 
sponding portion of other works, it has two obvious deficiencies — 
