322 Scientific Intelligence. 



biology. Two or three points may be briefly referred to, which 

 might be much enlarged on if our space would admit. In discussing 

 marine regions of distribution the author reaches this significant 

 conclusion, that the passage from the temperate to the polar 

 climatic zones does not constitute so important a climatic boun- 

 dary for the distribution of organisms as the passage from tropi- 

 cal to temperate. The most important climatic boundary is the 

 line where the sum of the general fluctuations of temperature is so 

 great that tropical organisms accustomed to an equable warm 

 climate are unable to endure the changes ; a greater reduction of 

 mean temperature is found farther poleward, this being associated 

 with the diminution of the amplitude of the fluctuation and is not 

 to be regarded as a climatic limit of first rank. 



In the chapter on the distribution of Decapods the conclusion is 

 reached that the ancestors of Decapods, as well as Euphausiacea, 

 were Nekton (open sea) animals, and as they were dependent upon 

 the substratum they could exist only under littoral and abyssal 

 conditions. 



In an interesting chapter on the favoring and hindering means 

 of distribution, the author emphasizes the importance of isolation, 

 and formulates the four following as the chief factors in the 

 formation of new species, viz: 1, Adaptation to external con- 

 ditions forms variations; 2, the transmission of adaptations 

 fixes the variations, thus occasioning groups of morphologically 

 similar forms ; 3, natural selection modifies these morphological 

 groups causing mutation in definite directions; 4, isolation of 

 the morphological groups produces differentiation and direction 

 of mutation and thus the production of separate species. We 

 hope to have, in a future number, a fuller discussion by the author 

 of some of thesQ points. h. s. w. 



4. Charles Ly ell and modern Geology ; by Prof. T. G. Bonney. 

 pp. 224, New York (Macmillan & Co.), 1895.— This is a brief but 

 readable account of the life of a geologist whom all the world 

 knows, but whose memory will be revived for the younger gener- 

 ation by this compilation. It is one of the Century Science Series 

 edited by Sir Henry Roscoe, and like others of the series the 

 brevity of the work is likely to lead earnest students to look up 

 the original biographies of these scientific worthies who have 

 made the present century famous. 



5. . Beitrage zur Geophysik. Zeitschrift fur Physikalische 

 Erdkunde. Herausgegeben von Prof. Dr. Georg Gerland. II 

 Band. 2-4 Heft. pp. 197-773, Stuttgart, 1895.— This part closes 

 the second volume of the valuable Beitrage zar Geophysik, edited 

 by Professor Gerland, the first volume of which was noticed in 

 volume xxxv (p. 344) of this Journal. Some of the papers here 

 included are: A. Schmidt, Erdmagnetismus und Erdgestalt ; E. 

 v. Rebeur-Paschwitz, Horizontalpendel-Beobachtungen auf der 

 Kaiserlichen Universitats-Sternwarte zu Strassburg ; E. Rudolph, 

 Ueber submarine Erdbeben und Eruptionen ; H. Wagner, Areal 

 und mittlere Erhebung der Landflachen sowie Erdkiuste. 



