102 CARNEGIE INSTITUTION OF WASHINGTON. 



Other matters of interest are cited below. 



(1) The demonstration that the sex-determiner apparently does not 

 lie in similar chromosomes in closely related species of Drosophila. 

 This opens up new and interesting difficulties in the study of the homol- 

 ogy of the chromosomes. 



(2) Evidence that male and female embryos of pigeons are different 

 in their metabolism. 



(3) Success in controlling the sex-ratio in certain aquatic entomo- 

 straca by varying the number of mothers in a unit of water. 



(4) A study of mammalian spermatozoa, showing that, unlike those 

 of some insects, they do not fall into two types in respect to size. 



(5) The demonstration of the possibility, in one strain of the sex- 

 intergrade Daphnia, of changing the degree of intergradeness by 

 selection. 



(6) The observation that a form of parasitism in Daphnia induces 

 sex-intergradism. 



(7) Age of mice greatly influences their susceptibility toward in- 

 oculated tumors; the reactions of a non-susceptible race to tumors is 

 to a remarkable degree related to the activity of the gonad. 



(8) Evidence has been secured that capacity for successful trans- 

 plantation of tissue (spleen) from one individual to another of the same 

 race depends upon the genetic uniformity of the race. 



(9) Evidence that in white cats the gametes carry lethal factors, 

 which operate even in the simplex condition. 



(10) The inauguration of a method of testing quantitatively the 

 instincts and intelligence of dogs. 



(11) The clear evidence that timidity has an inherited basis in dogs. 



(12) A demonstration that etherized non-waltzing mice fall into the 

 same three groups of dextral, sinistral, and neutral whirlers that are 

 found in Japanese waltzing mice. 



(13) The conclusion that in mating (of flies) where a close approxi- 

 mation to a 1 : 1 Mendelian ratio is expected, selection can isolate lines 

 in which the zygotic ratio departs widely in the desired direction from 

 the expected. 



(14) Evidence of non-disjunction in the fourth chromosome of 

 Drosophila. 



(15) A confirmation by statistical analysis of Schuster and Elder- 

 ton's conclusion as to the degree of inheritance of scholastic ability 

 between fathers and sons. 



(16) Clear statistical evidence of the existence of human cancerous 

 families. 



(17) The completion of a first quantitative study of inheritance of 

 musical ability, bringing evidence of its Mendelian behavior. 



(18) The development of formulas for calculating ancestral inheri- 

 tance. 



