Geology and Natural History. 83 



consists in part of the drawings and notes which they had made 

 some years ago with a view to issuing a supplementary volume 

 to include such rare, inconspicuous, or little known species as had 

 been found on the British coast during the many years that had 

 elapsed since the publication of their monograph. After their 

 death Sir Charles Eliot undertook the preparation of the volume, 

 and the great value of the work is largely due to the lucid dis- 

 cussion of the general anatomical features and relationships of 

 this group of animals from his pen. The chapters on variation 

 and distribution, bionomics, embryology and larval stages, and 

 classification, are treated on such broad biological lines as to be of 

 general interest, while the concluding chapter contains a synopsis 

 of the families, genera and species which occur in the Northeast- 

 ern Atlantic region, and brings up to date the nomenclature of 

 the forms which have been recorded during the more than half 

 century since the publication of the first seven parts of the work. 

 Of the 68 figures, 45 are reproduced from the drawings of Alder 

 and Hancock, while the remaining 23 have been drawn, mainly 

 from living animals, especially for the present volume, w. R. c. 



14. Medusae of the World; by Alfred Goldsborough 

 Mayer. 3 volumes, quarto. Washington, 1910. (Published 

 by the Carnegie Institution.) — Volume I, pp. 230 + xv, with 29 

 colored plates and 119 text figures, and Volume II, pp. 231 to 

 498 + xv, with 26 plates and 208 text figures, contain descrip- 

 tions of all the known Hydromedusae of the world and of such 

 hydroids as are known to produce medusae. Volume III, on the 

 Scyphomedusae, contains pp. 499-735, with 21 plates and 101 text 

 figures. This splendid monograph is by no means a systematic 

 treatise only, for it includes a discussion of all known facts 

 regarding the embryology, cytology and physiology of each 

 species. The large number of beautifully executed drawings on 

 the colored plates illustrate alike the artistic ability and tireless 

 energy of the author. w. r. c. 



15. An Introduction to Zoology ; by Robert W. Hegjster. 

 Pp. xii, 350, with 161 figures. ' New York, 1910 (Macmillan 

 Company). — This book represents a wide departure from the 

 customary plan of an elementary book in zoology in that its aim 

 is to illustrate the important biological principles by a compara- 

 tively thorough study of a very few types rather than by a super- 

 ficial study of a representative of each of the principal phyla. A 

 general discussion of the principles of biology, the phenomena of 

 life, the cell, and cell theory is followed by a comprehensive 

 study of the structure and life processes of Amoeba and Para- 

 moecium, with reference to certain other protozoa. The hydra, 

 worms, crayfish, and the honeybee represent the metazoa and are 

 treated with a special reference to the physiological peculiarities 

 of their various organ systems. An interesting chapter on the 

 history of zoology, with portraits of several of the earlier inves- 

 tigators, and a final chapter on the more important zoological 

 theories and the facts on which they are based, emphasize the 



