236 



NATURE 



[October 20, 192 1 



bird-portraiture, but its unrivalled merits are due 

 to the original descriptions of the birds in their 

 native surroundings, written by one who is in- 

 tensely imbued with an all-round love of Nature, 

 and endowed with a graceful pen — a combination 

 which has imparted a fascination to the graphic 

 descriptions of experiences in many cases unique. 

 A number of the haunts were reached only after 

 extraordinary difficulties had been overcome by 

 the author's indomitable perseverance, and in the 

 company of savages, some of whom were only 

 "nominally safe." Thus were the facts respect- 

 ing the home-life of certain little-known or wholly 

 unknown species obtained, and the photographs of 

 their abodes, which have been beautifully repro- 

 duced in photogravure, secured. The coloured 

 plates, twenty-four in number, are excellent, espe- 

 cially those by Mr. G. E. Lodge and Mr. Gron- 

 vold, while a series of maps illustrating the dis- 

 tribution of the various species adds to the worth 

 of a valuable and noteworthy contribution to orni- 

 thological hterature. W. E. C. 



Biitschli's Lectures on Comparative 

 Anatomy. 



Vorlesungen iiber vergleichende Anatomie. By 

 Prof. Otto Biitschli. 3 Lieferung : Sinnes- 

 organe und Leuchtorgane. Pp. iii + 643-93 1 -f 

 xiv. (Berlin: Julius Springer, 192 1.) 48 marks. 



THE first two parts of this text-book have 

 already been reviewed in Nature (in 191 1, 

 July 27, p. 104; and 1913, August 7, p. 577), and 

 the distinctive merits of the work have been indi- 

 cated. In the third part the excellence of the 

 semi-diagrammatic illustrations and the lucidity 

 of the exposition are fully maintained, although 

 the author died in 191 7, leaving the work un- 

 finished. The difficult task of completing the 

 work for this volume and seeing it through the 

 press has been achieved with conspicuous success 

 by Drs. Blochmann and Clara Hamburger. 



The work deals with the sense-organs and the 

 light-emitting mechanisms of both invertebrate 

 and vertebrate animals, and, as in the preceding 

 volumes, each structure is considered from a 

 broad, comparative point of view, and illustrated 

 with a wealth of diagrams. The reader can thus 

 acquire easily a clear conception of the varied 

 forms assumed throughout the animal kingdom 

 by the spries of sensory organs in the skin, the 

 peripheral instruments of smell and taste, and the 

 .organs of equilibration, hearing, vision, and light- 

 production. This method of treatment is of special 

 interest and importance to the vertebrate morpho- 

 logist. The latter experiences an increasing diffi- 

 NO. 2712, VOL. 108] 



culty in discovering what is known about inverte- 

 brate anatomy, some of which often becomes of 

 crucial importance in his researches. These con- 

 siderations apply with special force to the sense- 

 organs, and especially to those of vision, the 

 understanding of the structure of which in inverte- 

 brate animals is essential for the adequate appre- 

 ciation of the nature of the nervous arrangements 

 in the eyes of vertebrates. The vast significance 

 of the evolution of the sense-organs and their 

 nervous connections with the evolution of verte- 

 brate animals gives an additional interest to the 

 text, supplemented as it is by the fascinating 

 series of diagrams, which have been admirably 

 chosen and clearly reproduced. 



It is unfortunate that the authors, who must 

 have sifted a vast array of writings in collecting 

 the material for this volume, have omitted all 

 bibliographical references, the inclusion of which 

 would have trebled the value of the work. This 

 is particularly to be regretted in the case of the 

 light-emitting organs, for it is difficult for those 

 who become interested in the elusive physico- 

 chemical problems of these remarkable structures 

 to get on to the track of the biological literature 

 relating to them. G, Elliot Smith. 



Earth-structure. 



Der Bau der Erde. By Prof. Leopold Kober. 

 Pp. iv + 324-1-2 plates. (Berlin: Gebriider 

 Borntraeger, 192 1.) 80 marks. 



THIS handsomely printed work, with a 

 frontispiece, a folded map of general earth- 

 structure, and line-illustrations in the text, is, in 

 spite of its nominal price, a welcome sign of 

 scientific recovery. The absence of an index is 

 surely an accident which its well-known publishers 

 will redress. Perhaps the most striking feature, 

 and one that will encourage general use, is its 

 crisp lucidity of style. We have selected at 

 random ten consecutive sentences. They contain a 

 total of 133 words, and one consists of six words 

 only. This shows the German-Austrian language 

 at its best, and we should like to attend Prof. 

 Kober's lectures. His main thesis is that the 

 building of folded mountain-chains is a process of 

 " revolution " following on one of " evolution," in 

 which geosynclinals have been formed. A geosyn- 

 clinal represents what we sometimes regard as an 

 epoch of quiescence. Its sinking base ultimately 

 becomes nipped between two rigid masses of the 

 lower crust, and the sedimentary accumulation 

 rises in folds and overfolds at the surface. Moun- 

 tain-building is the close of a cycle, and is a mani- 

 festation of the continuous contraction of the sub- 



