DEPARTMENT OF EXPERIMENTAL EVOLUTION. * 



C. B. Davenport, Director. 



Among the principal advances of the year have been: (1) the origin 

 from a hne of parthenogenetic entomostraca of a strain that produces 

 both sexes, in the same individual, in varying proportions; and the 

 analysis of this condition; (2) the demonstration that, so far as studied, 

 similar factors occupy siixiilar chromosomes and have similar intra- 

 chromosomal relations in various different species of Drosophila, 

 affording additional evidence of the fundamental nature of the struc- 

 tural mosaic of the germ-plasm; (3) the unraveling of the germinal 

 factors present in the yellow daisy (Rudheckia hirta) and the study of 

 the numerous mutations that are arising in our strains ; (4) the demon- 

 stration that the blood-plasma of fowls differs in the two sexes in fat 

 and phosphorus content in the same way that pigeon eggs of pros- 

 pectively different sex differ; (5) the demonstration of the inferiority, 

 in solving the problems of the multiple-choice apparatus, of the off- 

 spring of alcoholic as contrasted with non-alcoholic parents; (6) the 

 demonstration of dominant shortening factors in the genetic control of 

 human stature ; (7) the completion of the second volume of the unpub- 

 lished scientific work of Professor Whitman. 



STAFF. 

 The work of this Department during the present year has been 

 carried on by seven resident investigators and various associates and 

 assistants. Staff meetings have been held weekly, at each of which a 

 member of the staff reported on his own work. In addition to his 

 other duties the Director has continued his analysis of the data of 

 human inheritance, especially stature and the elements of success in 

 achievement. In this he has been assisted by Miss Mary T. Scudder. 

 Dr. J. A. Harris and his assistants have made an investigation of 

 selective death-rate that has required the raising of 600,000 seedhng 

 beans. He has also spent some weeks in the Everglades region of 

 southern Florida and in the neighborhood of the Desert Laboratory, 

 southern Arizona, studying the physico-chemical properties of vege- 

 table saps in their relation to environmental factors. Dr. A. M. Banta 

 has continued the cave experiments, but has put most of his time on the 

 work of selecting daphnids for sensitiveness to light, continuing 

 parthenogenetic strains, attempting to control sex, and breeding sex 

 intergrades. Dr. Riddle has continued his editorial work on the 

 Whitman manuscripts and data and his studies on the control of sex in 

 pigeons. Dr. E. C. MacDowell has carried on investigations into the 

 modifiability of the germ-plasm and the effects of ''selection" in the 



*Situated at Cold Spring Harbor, Long Island, New York. 



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