82 American Fisheries Society 



value. The leeches are discussed in a very satisfactory manner 

 by Dr. J. Percy Moore. The very full treatment of the wheel 

 animalcules or rotifers, by Prof. H. S. Jennings, is a delight to 

 the zoologist. The numerous smaller Crustacea, so important as 

 fish food and in some cases as parasites, are handled by well 

 known specialists, A. S. Pearse (Phyllopoda) , E. A. Birge (Clado- 

 cera), C. Dwight Marsh (Copepoda), and R. W. Sharpe 

 (Ostracoda). Of the chapter on the higher crustaceans it is 

 sufficient to say that it is the work of Dr. E. A. Ortmann. The 

 aquatic insects and mollusca are so numerous that a volume 

 would be required for the full discussion of either group, yet Prof. 

 Jas. G. Needham has accomplished a great deal in the seventy 

 pages alloted to the former group, and Dr. Bryant Walker has 

 also done much with the mollusca, considering the limited space. 



It must be borne in mind that this is not merely a systematic 

 work, but that much space is devoted to ecological and economic 

 aspects of the various forms, to life histories and other general 

 biological considerations. 



The whole volume is profusely illustrated, and all the cuts are 

 new and drawn from specimens. Keys are provided in all groups 

 except the higher plants and the vertebrates, and the most 

 important reference works on each group are cited in a literature 

 list at the end of each chapter. The index is very complete. 



As stated in the author's preface this is the first attempt "to 

 deal with North American fresh-water life in its entirety." While 

 such a work is necessarily incomplete, even in a large volume, 

 there is great value in the accumulation of such a mass of material 

 from scattered sources, as it is thus rendered available for the 

 general worker as well as for the specialist. Fisheries men and 

 other individual workers interested in the life of the fresh waters 

 of North America will all welcome this volume, and for the colleges 

 and aquatic laboratories it will be a necessity. 



R. C. OSBURN. 



