254 



The T 



oiirnal o 



f Heredity 



certain that the two species mate, but 

 it is barely possible that the species 

 cross is unpro(lucti\'e. 



We can hardly pass o\'er our records 

 without commenting upon the great 

 preponderance of females observed in 

 our experiments. Out of a total of 

 53 indi\iduals liorn in our pedigreed 

 cultures, 16 were males while 37 were 

 females. If the males and females are 

 equally probable, in accordance with 

 our usual present concept, then 26.5 of 

 each sex is the most probable expecta- 

 tion. The deviation of 10.5 in our 

 obser\'ed records from the theoretical 

 is 4.28 X the probable error of simple 

 sampling, 2.455. The odds against 

 de\'iations of this and greater magni- 

 tudes are about 250 to 1. The ob- 

 served ratio is therefore not impossible 

 on the basis of a theory which calls for 

 an equal number of the males and 

 females, but raises a legitimate suspi- 

 cion that the zygotes classified at 

 birth may be the residue left after 

 consideral)le prenatal selection and 

 elimination. After all, the theory is 

 meant to apply only in a strict sense 

 to zygotes formed, rather than to 

 zygotes classified. 



Summarizing, we may say that we 

 have found fifteen mutant skimks, 

 which fall into five types. The three 

 different albinotic types represent sim- 

 ple changes in single genes and there- 

 fore each gives a monohybrid ratio 

 when crossed to the wild form. There 

 is no e\'idence that they may be multi- 

 ple allelomorphs. In fact, the two 



more extreme forms of albinism give 

 some evidence to the contrary. Our 

 records showed a great preponderance 

 of females o\cr males. 



Mutations are relatively abundant 

 in the genus Mephitis. The occurrence 

 of self black, or blue, or siher types is 

 probably only a matter of time and 

 opportunity to obser\'e large numbers. 

 When such occur, they can be per- 

 petuated without much doubt, in the 

 same manner we used to increase the 

 number of whites. A knowledge of 

 simple Mendelism would suffice for 

 such cases. Since our skunks seemed 

 to be so susceptible to the effects of 

 inbreeding, we would modify our pro- 

 cedure in the following way: — by 

 breeding unrelated Fi hybrids from 

 similar mutants or by breeding Fi half 

 brothers and sisters from a single 

 mutant to obtain more \'igorous segre- 

 gates in the F2. At least we should tr>' 

 this method to see if it might not per- 

 haps have some advantages over the 

 usual mating of Fi sibs together. 



Selection for the reduction of white or 

 for increased size would be effective we 

 believe, but we would resort to mass 

 selection, in order to avoid close breed- 

 ing. One might perhaps find strains 

 which are not so sensitive to inbreeding 

 as our skunks proved to be, in which 

 case one could select more rigidly. If 

 some species crosses are found to be 

 possible, increased size might be se- 

 cured in that way by the usual hybridi- 

 zation methods. 



American Association for the Advancement of Science 

 Meeting in Toronto, December 27-31, 

 1921 



The 74th meeting of the A.A.A.S. 

 and affiliated societies is being held 

 this year in Toronto, Canada by invi- 

 tation of the I'niversity of Canada 

 and the Royal Canadian Institute. 

 While this is not one of the larger, 

 four-yearly meetings of the Society 

 and therefore will not be so comj)lex 

 as the one held in Chicago last year, it 



is expected to be of exceptional interest 

 on account of its international charac- 

 ter. Scientific workers from the two 

 English-speaking nations will have 

 opportunities for strengthening the 

 bonds of mutual understanding and of 

 personal and national friendship. Sev- 

 eral British scientists may also be 

 present to address the sessions. Many 

 members of the American Genetic 

 Association will be in attendance and 

 present papers. 



