590 



SCIENCE. 



[N. S. Vol. XXIV. No. 619. 



end of the book, furnish a good introduction 

 to these subjects. 



Then follow the chapters embodying the 

 'biological treatment' comprising the greater 

 part of the text (183 pages). Their titles are 

 the following : Adaptations of Aquatic Insects, 

 Color and Coloration, Adaptive Coloring, 

 Origin of Adaptations and of Species, Insects 

 in Relation to Plants, Insects in Relation to 

 Other Animals, Interrelations of Insects, and 

 Insect Behavior. While these subjects are 

 not new to entomological text-books, they are 

 here given a new treatment and merited 

 prominence, and entomologists will appreciate 

 having them brought together for discussion 

 in one place. 



Then follow chapters on Distribution, and 

 on Insects in Relation to Man, the latter being 

 a discussion of the mission of the economic 

 entomologist and a historical sketch of the 

 evolution of that species in America. The 

 economic entomology of the book is mostly in 

 the title, where it, perhaps, serves the pub- 

 lisher's purpose. There is no mention of 

 many of the most important economic species, 

 nor of the most important methods of eco- 

 nomic procedure. The book concludes with 

 a good bibliography, of 57 pages. 



The typography and press work are excellent. 

 Mistakes are few; but in the short chapter on 

 adaptations in aquatic insects the following 

 are noted: The figure of the hind leg of the 

 diving beetle Cyhister on page 187 fails to show 

 the inferior spur greatly widened — the char- 

 acter by which this genus is most readily recog- 

 nized; the figure of Simulium larva on page 

 190 does not show the anal gill tuft, although 

 illustrating a paragraph on gills; it is doubt- 

 less by oversight that the larvae of Ephemeridae 

 are mentioned on the same page along with 

 those of the Odonata as having a highly de- 

 veloped rectal respiration. The style is never 

 prolix, and although verbal infelicities are 

 rather too frequent, the meaning is rarely 

 obscure. The illustrations are always appro- 

 priate, and generally of a high order. The 

 book as a whole is excellent, and will be most 

 useful to the general student. 



J. G. N. 



The Elements of Geology. By William Har- 

 mon Norton. Ginn and Co. 1905. 

 This volume has been written, the author 

 tells us, to fill the need of a text-book that 

 shall knit cause and consequence in geology 

 together, ' to treat land forms and rock struc- 

 tures in connection with the geologic processes 

 causing them,' abandoning the traditional divi- 

 sion of the subject into departments, dynam- 

 ical, structural, physiographical and historical. 

 As a matter of fact, he preserves the last of 

 these, so the new departure must be looked for 

 in the rest of his book, ' External Geological 

 Agencies and Internal Geological Agencies.' 

 We readily obtain an idea of the treatment 

 attempted by comparing Professor Norton's 

 book with a well-known predecessor. For 

 this I have put equivalent parts of LeConte's 

 text-book and this on the same lines of parallel 

 columns. It thus appears that our author has 

 omitted the ' Structural Geology ' and some 

 of the ' Organic Agencies ' and put the rest 

 under slightly different heads : 



Norton. 

 I. External Geological 



Agencies. 

 II. Internal Geological 

 Agencies. 

 (Touched in I.) 

 (Touched in I. and II. ) 

 III. Historical Geology. 



LeConte. 

 I. Dynamical Geology, 

 f 1. Atmospheric Agencies. 

 1 2. Aqueous Agencies. 



3. Igneous Agencies. 



4. Organic Agencies. 

 II. Structural Geology. 



III. Historical Geology. 



Of LeConte's organic agencies, peat is de- 

 scribed by Norton under river deposits, lime 

 accumulations under offshore and deep sea 

 deposits, and the bog ore, silicious and phos- 

 phatic deposits that get a brief mention in 

 LeConte are not here referred to. 



Of the structural geology, general form and 

 structure of the earth are omitted as far as I 

 have been able to learn, sedimentary rocks are 

 treated in several places, one half page in the 

 Introduction, five pages in the Work of the 

 Weather, twenty pages in Offshore and Deep- 

 sea Deposits, six pages in River Deposits and 

 about three pages in the Work of the Wind. 

 Igneous and metamorphic rocks are treated 

 under internal agencies, joints under the work 

 of the weather and movements of the earth's 

 crust, faults under movements of the earth's 

 crust, mineral veins under work of ground 

 water and metamorphism and mineral veins,. 



