Apeil 8, 1898.] 



SCIENCE. 



501 



The Popular Science Monthly gives a portrait 

 of Charles Semper as frontispiece and contains 

 a sketch of his life. The most interesting arti- 

 cle in the number is one by Professor W. K. 

 Brooks on 'Migration,' but many will read with 

 equal interest the article on ' Evolution and 

 Teleology,' by Dr. J. A. Zahm, presented be- 

 fore the recent Catholic Scientific Congress. 

 Among the other papers is one on ' Criminal 

 Anthropology in Italy,' by Miss Helen Zim- 

 mern, and one ou the ' Electric Transmission of 

 Water Power,' by Mr. William Baxter, Jr. The 

 number also contains three extended articles 

 on economic topics. 



The Astronomical Journal for March 28th is 

 greatly enlarged to make place for Dr. T. J. J. 

 See's discoveries and measures of double multi- 

 ple 'stars in the southern hemisphere. The 

 first catalogue contains 500 entries, the results 

 of work during the first year and four months 

 at Flagstaff and Mexico. 



SOCIETIES AND ACADEMIES. 



BIOLOGICAL SOCIETY OF WASHINGTON — 290TH 



MEETING, SATURDAY, MARCH 26. 



The evening was devoted to a ' Symposium 

 on the Comparative Value of Factors Influenc- 

 ing the Distribution of Life,' the subject being 

 introduced by Dr. C. Hart Merriam, whose re- 

 marks were particularly directed to those fac- 

 tors governing the distribution of terrestrial 

 life. The most important of these he con- 

 sidered to be temperature, next humidity [and 

 the elevation of the base level. The effects of 

 the general slope of elevated regions was dis- 

 ■cussed and its influence in extending or cur- 

 tailing the various life zones according as the 

 slope was towards the north or south. The 

 twofold effect of streams was dwelt on, par. 

 ticularly of rapid mountain streams, along 

 whose sides is a narrow border of northern 

 forms, while valleys produced by erosion per- 

 mit the entrance of southern species. 



Dr. L. O. Howard spoke of the distribution 

 of insects and considered the prime factors to 

 be : 1. Temperature as influencing all groups ; 

 2. Distribution of food plants as influencing 

 phytophagic species and the species dependent 

 upon them ; 3. The capacity of the species to 



conquer in the struggle for existence ; 4. The 

 influence of civilization. He dwelt especially 

 upon the complicated inter-relationships among 

 insects and showed that restriction in distribu- 

 tion due to an apparently obvious cause might in 

 many cases in reality be due to a perfectly blind 

 cause, due to these interrelations of forms. 



Dr. W. H. Dall spoke of the distribution of 

 aquatic mollusks, considering temperature to 

 be the preponderating factor, largely so through 

 its effects ou very young mollusks. Thus adults 

 could live and thrive where the temperature 

 was fatal to the young. Pressure was stated 

 to have little effect, some species ranging from 

 a depth of three fathoms to 1,700 fathoms. 

 Abyssal forms were said to be of wide distribu- 

 tion, while those found above 500 fathoms were 

 generally derived from littoral species. 



Mr. F. V. Coville, speaking of plants, said 

 that the factors influencing their distribution 

 were in some respects quite different from 

 those affecting animals. For example, plants 

 had no power of choice and could not remove 

 from the place when their seeds fell, however 

 unsuitable it might be. The temperature of 

 the soil was another powerful factor affecting 

 plants, as well as the character of the soil itself 

 and its drainage, and, above all, the amount of 

 moisture it received. 



Dr. Theo. Gill said that temperature was an 

 element affecting large aggregates of animals 

 and that other causes influenced the smaller 

 groups. The geological history of the earth 

 had very much to do with the present distribu- 

 tion of terrestrial life ; and while temperature 

 was the great factor in determining the extent 

 and character of marine faunas, temperature 

 subject to the lay of the land governed the dis- 

 tribution of life on land. 



Mr. B. E. Fernow said that the struggle for 

 existence must be taken into account and that 

 the ability of a plant to adapt itself to the 

 environment frequently accounted for an ex- 

 tended or restricted range. Thus a plant of 

 limited range in one country, when removed 

 to a region where it was not subject to the com- 

 petition of other forms, might spread with great 

 rapidity. 



Professor B. W. Evermann spoke of the influ- 

 ence of great drainage areas on fresh-water fishes 



