334 SCIENCE PROGRESS 



and biologists the world over. The autho r undoubtedly has indicated the lines of 

 advance and frankly faced the difficulties that are still to be solved. 



C. H. O'D. 



Fresh-Water Biology. By Prof. H. B. Ward and Prof. G. C. Whipple, 

 with the collaboration of a staff of Specialists. [Pp. ix + mi, with 1547 

 figures.] (New York : John Wiley & Sons ; London : Chapman & Hall, 

 Ltd., 1918. Price $6, or .£1 8s.) 



This volume treats of the fresh-water life on the North American Continent, 

 and it may be said from the outset that it is quite indispensable to any biological 

 laboratory there and also to any worker in this subject. It should prove in- 

 valuable as a work of reference in schools where the teachers wish to pursue 

 biological questions a little more deeply than is done in ordinary text-books of 

 nature-study or natural history. Even in other countries it will be valuable 

 because of its general introductory account of all sides of hydrobiology, the special 

 introductions to the various chapters on groups of organisms and the bibliographies 

 at the terminations of the various sections. By means of its keys it should be 

 possible to run down fairly easily, at any rate, the genus of any of the lower 

 organisms or invertebrates found in North America. 



Here it should be remarked that it is a pity that the chapter on the vertebrates 

 is not modelled more on the lines of other chapters. It is, of course, obvious that 

 vertebrates, particularly fish, with their limited distribution, do not present the 

 same problem as the invertebrates, but in spite of this we think greater uni- 

 formity might have been secured. 



Several points in the book call for commendation. The plan adopted in the 

 chapter on Cladocera of giving with each drawing a line and its measurement is 

 one that might be extended to other chapters with advantage in future editions 

 of the book. In the section on Rotatoria the drawings are on one page and the 

 text facing them, and this too makes the figures more easy to read, and might be 

 adopted with benefit in other chapters. 



The difficulty in a compendium of this nature is to keep the book of a 

 reasonable size and yet make it comprehensive, and in this the editors have 

 succeeded admirably. More detail could have been given in some cases, but not 

 without increasing the size of the book ; indeed it is remarkable how much has 

 been included in its pages. 



The authors, one and all, are to be congratulated on producing a thoroughly 



useful, readable, and much-needed book. 



C. H. O'D. 



ANTHROPOLOGY 



The Megalithic Culture of Indonesia. By W. J. Perry, B.A. [Pp. xii + 198, 

 with 4 maps, 4 plates, and 9 other illustrations.] (London: Longmans, 

 Green & Co , 1918. Price 12s. bd. net.) 



This book is a contribution to the discussion of the problem known as culture- 

 mixture. The conception of culture-mixture as the explanation of various puzzling 

 sociological phenomena which are to be observed among many peoples is a theory 

 which has been developed mainly by Dr. W. H. R. Rivers and Prof. G. Elliot 

 Smith. " In the course of an examination of the cultures of Melanesian peoples, 

 Dr. Rivers came to the conclusion that the only way to account for the existence 

 of certain customs among the people of Melanesia was to adopt the hypothesis of 



