SCIENCE 



Friday, Aeril 4, 1913 



COl^TENTS 



The American Association for the Advance- 

 ment of Science: — 

 The Significance of Pleistocene Mollusks: 

 ,,. Professor Bohumil Shimek 501 



jiamsay Heatley Traquair: Db. L. Hussakop 509 



John Shaw Billings 512 



The Carnegie Foundation for the Advance- 

 ment of Teaching 512 



The Pacific Association of Scientific Societies 514 



Scientific Notes and News 514 



University and Educational News 517 



Discussion and Correspondence: — 



The Complexity of the Mioroorganic Popu- 

 lation of the Soil: Dr. E. J. Eussell. 

 Two Additions to the Mammalian Fauna 

 of Michigan: Norman A. Wood. Inter- 

 glacial Becords in New York: De. Frank 

 Collins Baker. Entamosba tetragena and 

 Entamceba hystolytica: Db. S. T. Darling. 

 Indoor Humidity: Dr. L. R. Ingersoll . . 519 



Scientific Books: — 



Pieron on Le prohleme physiologique du 

 Sommeil: Professor W. H. Howell. 

 Howard, Vyar and Knap 's The Mosquitoes 

 of North and Central America and the West 

 Indies: Professor T. D. A. Cockerell. 

 Blakeslee and Jarvis's Trees in Winter: 

 Professor Charles E. Besset. Whet- 

 ham's Science and the Human Mind: Pro- 

 fessor B. M. Wenlet 525 



Notes on Entomology: De. Nathan Banks 530 



Special Articles: — 



Palmesthetic Beats and Difference Tones: 

 Dr. Knight Dunlap. Echinoderm Hyhrid- 

 ization: De. David H. Tennent 532 



Societies and Academies: — 



The Academy of Science of St. Louis: Pro- 

 fessor G. 0. James. The Anthropological 

 Society of Washington: W. H. Babcock . 537 



MSS. intended for publication and books, etc.. intended for 

 review should be sent to Professor J. McKeen Cattell, Garrison- 

 on-Hudson, N. Y. 



THE SIGNIFICANCE OF PLEISTOCENE 

 MOLLVSKS ' 



In the investigation of natural problems 

 the most conspicuous or bulkiest character 

 does not always furnish the most con- 

 vincing evidence. We readily see the mass 

 of diatomaceous earth, but we do not under- 

 stand its gritty quality, nor can we appre- 

 ciate its origin until we have studied the 

 minute, individually almost negligible frus- 

 tules which make it up ; sandstones or lime- 

 stones may form great cliffs, but it requires 

 the comparatively insignificant fossil to 

 finally reveal the origin and the place of 

 the rock. Similarly, in the study of the 

 Pleistocene we encounter gross features 

 which have their value — we find variously 

 comminuted and diversely arranged ma- 

 terials in great bulk; we find topographic 

 and physiographic characters on a large 

 scale ; yet the best evidence which we have 

 concerning the conditions under which cer- 

 tain parts of the Pleistocene formations 

 were deposited is furnished by the fossils 

 which usually form a small and not always 

 conspicuous part of the deposits. 



Both plant and animal fossils have been 

 found in the various subdivisions of the 

 Pleistocene. The former consist chiefly of 

 the leaves and wood of gymnospermous and 

 angiospermous trees and shrubs, mosses 

 and diatoms; the latter of some insects, a 

 conspicuous, though limited, mammalian 

 fauna, and the mollusks which form the 

 most widely distributed and most uni- 

 versally present group of all. 



' Address of the vice-president and chairman of 

 Section E — Geology and Geography — American 

 Association for the Advancement of Science, 

 Cleveland, 1912. 



