150 



SCIENCE 



[N. S. Vol. XLVII. No. 1206 



sas Agricultural College; Charles D. Walcott, 

 Smithsonian Institution; Charles Zeleney, Univer- 

 sity of Illinois. 



On Saturday evening members of the Natural- 

 ists and of the aflEiliated societies attended a 

 smoker given by the biologists of Pittsburgh at 

 Carnegie Music Hall. 



A symposium was presented in the afternoon 

 session on the subject, Factors of organic evolu- 

 tion. 



Climatic change as a factor in organic evolu- 

 tion, by Ellsworth Huntington. (Eead by 

 title.) 



Migration as a factor in organic evolution, by 

 C. C. Adams. 



Method of reproduction as a factor in organic 

 evolution, by E. M. East. (Eead by title.) 



Mutation as a factor in organic evolution, by T. 



H. MOEGAN. 



Mendelian inheritance as a factor in organic 

 evolution, by C. B. Davenport. 



Natural selection as a factor in organic evolu- 

 tion, by J. Arthur Harris. 



Disease as a factor in organic evolution, by 

 Theobald Smith. (Bead by title.) 



Intelligence as a factor in organic evolution, by 

 E. M. Yerkes. (Eead by title.) 



In addition to the symposium the ■ following 

 papers appeared upon the program: 



Sex intergrades in Cladocera and their signifi- 

 cance, by A. M. Banta. 



A demonstration of the origin of two pairs of 

 female twins from two eggs of high storage meta- 

 bolism, by Oscar Eiddle. 



Changing the sex ratio in the rat through in- 

 breeding, with selection, by Helen D. King. 

 (Eead by title.) 



Changes in sexuality in plants, by A. B. Stout. 



Mutations in Datura, by A. F. Blakeslee. 



Nutritional effects influencing the development 

 of maize hybrids, by D. P. Jones. (Eead by title.) 



The inheritance of variations in the marginal 

 spines of Silvanus surinamensis, by Marian E. 

 Hubbard. (Eead by title.) 



Parthenogenesis and inheritance in the grouse 

 locust, Appotettix sp.?, by E. K. Nabours. 



The r6le of approaching extinction in evolution, 

 by L. E. Griffin. 



TicTcing, handing and silvering factors in cats in 

 relation to the problem of mimicry, by P. W. 

 Whiting. 



Variations in somatic chromosome numbers, by 

 R. T. Hance. 



Eleven matings in a species with heteromorpJiic 



tetrads; recombinations expected in the F„ by E. 

 Eleanor Carothers. (Read by title.) 



Sex-determination in a parasitic wasp, Hadro- 

 bracon brevicornis Wes., by P. W. Whiting. 

 (Eead by title.) 



The influence of sex on the color pattern of 

 guinea-pigs, by Sewall Wright. 



Atrophic fetuses in yellow mice and zygotic elimi- 

 nation, by J. A. Detlefsen. (Read by title.) 



Fluctuations of sampling in a Mendelian popu- 

 lation in mice, by J. A. Detlefsen. (Eead by 

 title.) 



On the hybridity of Entylia sinuata Fab. and its 

 forms occurring in nature, by S. I. Kornhauser. 

 (Eead by title.) 



The independence of the germplasm and soma 

 in Thelia bimaculata Fab., by S. I. Kornhauser. 



The distribution of granular pigment in the hair 

 of guinea-pigs, by H. E. Hunt and Sewall 

 Wright. 



Histological studies on trimerous bean seed- 

 lings, by J. Arthur Harris and J. T. Penny- 

 packer. (Eead by title.) 



Tlie r6le of factor mutations in evolution, by E. 

 B. Babcock. (Eead by title.) 



The result of cousin marriages through N gene- 

 rations, by F. A. Spragg. 



Germinal changes in the bar-eyed race of 

 Drosophila during the course of selection for 

 facet number, by Charles Zeleney. 



The genetic and somatic relationship between 

 vestigal and miniature wings in Drosophila ame- 

 lophila, by Oreen Lloyd-Jones and F. S. Hultz. 



The Naturalists' dinner was held on the evening 

 of January 1 at the Hotel Sehenley with fifty in 

 attendance. The address of the president, Dr. 

 George H. Shull, was entitled "The genotype and 

 its environment." 



The officers of the society for 1918 are: 



President — ^William E. Castle, Harvard Univer- 

 sity. 



Vice-president — Guy N. , Collins, United States 

 Department of Agriculture. 



Secretary — Bradley M. Davis, University of 

 Pennsylvania (1917-19). 



Treasurer — J. Arthur Harris, Carnegie Station 

 for Experimental Evolution (1918-20). 



Additional members of the executive committee 

 — Leon J. Cole, University of Wisconsin (1918) ; 

 Frank E. Lillie, University of Chicago (1916-18) ; 

 Eaymond Pearl, Maine Agricultural Experiment 

 Station (1917-19) ; George H. Shull, Princeton 

 University (1918-20). Bradley M. Davis, 



Secretary for 1917 



