502 THE AMERICAN NATURALIST. [VoL. XXXVI. 
On the 29th of December, 1900, two females carrying eggs were 
Mr. J. B. Babcock of the California State Fish Commission. These 
were procured in the market and had been caught in San Francisco 
Bay. The eggs of one of these were in various stages of gastru- 
lation, while the others were older, showing slight pigmentation of 
the eyes. During the following summer, while aboard a fishing 
steamer off the California coast, I was shown six females “in berry.” 
In one of these the embryos were half-developed zoéas, and the 
young of another were only slightly more advanced, while the 
remaining carried larva almost ready to burst their membranes. 
The captain of the vessel stated that he had taken egg-bearing 
females in every month of the year, and that the “yellow eggs” 
(young stages) occurred from the first of October until some time 
in January. This statement is supported by the discovery of seven 
other females taken off Moss Landing in Monterey Bay during 
January, 1902. All these carried eggs, which were in various 
stages, ranging from late gastrulation to half-developed zoéas. 
It thus appears that the breeding season of Cancer magister com- 
mences in the late summer or during the autumn and usually 
continues until some time in the following summer. H. H. 
Pratt's Invertebrate Zoölogy.! — This new book by Professor 
Pratt of Haverford College consists of a series of directions and 
descriptions for the guidance of students in their laboratory work 
in connection with comparative anatomical study of invertebrated 
animals. The types for study are selected from the following groups 
and in the order named: insects, myriapods, Crustacea, annelids, 
platyhelminths, Bryozoa, mollusks, ascidians, echinoderms, Hydrozoa, 
sponges, Protozoa. Several types from each of the important phyla 
are treated, and thus within groups the practical study is made truly 
comparative. This is important, for such comparisons. as untrained 
students can make for themselves are necessarily limited in the 
usual series of types with a single representative of each important 
phylum. Another valuable feature of these practical directions is 
that each lesson is complete in itself, so that the sequence of types 
may be varied at the will of the teacher. This is also of advantage 
in selecting the exercises of which the book contains more than 
ordinarily can be accomplished in a single year's course. The 
author suggests the possibility of beginning with the last lessons on 
1 Pratt, H. S. Znvertebrate Zoology. Boston, Ginn & Company, 1902. 210 pP- 

