421 



matter should have been spread out to form a book at all, and 

 why such, for the most part, poor scratchy diagrams should have 

 been used to illustrate it, is not at all clear. No doubt the book 

 will serve a useful purpose if it gets into the right quarters, 

 i.e. among those who have never seen a work on the microscope 

 and microscopic objects before ; but with so many other elementary 

 books on these subjects already published there can scarcely have 

 been any real call for the present work. 



D. J. S. 



EiNFACHSTE Lebensforme:n^ des Tier- und Pflanzenreiches. 

 Naturgeschichte der Mikroskopischen Siisswasserbewohner. 

 By B. Eyferth. Third Edition : completely revised and en- 

 larged by Dr. W. Schonichen and Dr. A. Kalberlah. viii 

 + 556 pages, 16 plates. Brunswick, 1900 : Benno Goeritz. 

 Price 20 marks. 



Although this is called a third edition of Eyferth's " Einfachste 

 Lebensformen," it is to all intents and purposes a new book, as it 

 has been almost entirely re- written and very much enlarged by 

 Drs. Schonichen and Kalberlah. Unlike Lampert's " Das Leben 

 der Binnengewasser," reviewed in the previous number of this 

 Journal, which gives much prominence to biological details, the 

 work now under notice is essentially a systematic work, the 

 bulk of the text consisting of brief descriptions of genera and 

 species, and keys. The latter are quite a feature of the book. 

 There are keys to the classes, keys to the orders, keys to the 

 genera, keys to the species, and even occasionally keys to 

 varieties. But there are also very useful, though short, intro- 

 ductory paragraphs to all the groups of organisms dealt with. 

 These are confined to the simplest forms of pond-life — the 

 Bacteria, Algse, Protozoa, and Rotifera, though perhaps the 

 Rotifer-lovers will hardly think that their pets should ba 

 described in this way. 



The editors do not claim to have incorporated every known 

 species in their work, as this, they think, would have made the 

 book much too large. They hav^e, however, endeavoured to give 

 practically all the valid European fresh- watt r genera and a large 

 proportion of the species, with an illustration of one species from 

 each genus. In this way they have produced a book which 



