270 EXPERIMENT STATION EECORD. 



On the relation of race crossing' to the sex ratio, Maud D. and R. Pearl 

 {Biol. Bui. Mar. Biol. Lab. Woods Hole, 15 {1908), No. J,, i)p. 194-205; abs. in 

 Jour. Roy. Micros. Soc. [London], 1909, No. 1, p. 33). — The authors discuss the 

 prevalent opinion among practical stock breeders that hybrids show an exces- 

 sive proportion of males and they report a statistical study of the effect of 

 hybridization on the human race. 



" Statistics of over 200,000 human births extending over a period of 10 years 

 in the city of Buenos Aires show that the proportion of males to females is 

 significantly greater when the parents are of different I'acial stocks than when 

 they are of the same. In the data are involved three racial stocks in pure 

 and cross matings. The preponderance of males in the offspring of cross 

 inatings appears not to be capable of explanation as the result of environmental 

 or demographic influences. Experimental investigations are necessary in order 

 to reach adequate explanations of such statistical facts regarding sex ratios as 

 are set forth in this paper." 



On the sex of hybrids in the family of Phasianidse, M. F. Guyer {Compt. 

 ■ Rend. Soc. Biol. [Paris], 65 {1908), No. 37, pp. 6Ji2-6.'i4; abs. in Jour. Roy. 

 Micros. Soc. [London], 1909, No. 2, p. 116). — Of 61 museum si)ecimens of 

 hybrids of pheasants, turkeys, peacocks, and barnyard fowls the sex was not 

 noted in 10 cases, was male in 47, and female in 4. It is suggested that the 

 predominance of males may be due to defective nutritive conditions, associated 

 with two dissimilar germ plasms. 



On the sex of hybrid birds, M. F. Guter {Biol. Bui. Marine Biol. Lab. 

 Woods Hole, 16 {1909), No. //, pp. 193-198).— The data reported are noted above. 



On the principles of heredity as applied to the production of new forms of 

 plants and animals, A. Dendy {Jour Roy. Soc. Arts, 57 {1909), No. 29.'i7, pp. 

 525-534, dgms. 2). — This is a popular article on Mendel's law and its signifi- 

 cance for the px'actical breeder. Recent instances are cited to show how new 

 varieties can be produced by combining unit characters. Concerning the in- 

 heritance of acquired characters the author says : " From the nature of the 

 case it appears extremely doubtful whether we shall ever be able to find a 

 practical solution of this problem," 



On some features in the hereditary transmission of the self-black and the 

 "Irish" coat characters in rats, I, G. P. Mudge {Proa. Roy. Soc. [London], 

 Ser. B, SO {1908), No. B 537, pp. 97-121, dgm. 1, charts 3).— From a study of 

 Mendelian inlieritance in rats the following results were obtained: 



Black is dominant to albinism, though not complete. There appear to be 

 two " Irish " types, and one and possibly both are heterozygotes. The carrying 

 power of albinism of rats is similar to albinos of mice and rabbits. Self-gray 

 types may carry both black and piebald recessive. Piebald black-white type 

 may be homozygous or black and piebald, or may carry albinism recessive. 



On some features in the hereditary transmission of the albino character 

 and the black piebald coat in rats, II, G. P. Mudge {Proc. Roy. Soc. [London], 

 Scr. B, 80 {1908), No. B 5',l, pp. 388-393).— \w this second paper the author 

 reports results of matings with albinos and piebald rats. 



Albinos when mated breed true to albinism whether their ancestors were 

 pigmented or not. When a piebald black rat is mated with a similar one two 

 different classes of offspring may occur: («) All black piebalds; or {b) a 

 mixture of black piebalds and albinos in nearly equal numbers. A piebald 

 black rat mated with an albino may give five different results, due to the 

 gametic nature of the albino employed. 



Influences of pure-bred sires, H. E. Van Norman {Pennxylrania Sta. Rpt. 

 1908. pp. 129-145, pi. 1). — For the past 17 years records have been kept of a 

 herd of grade Guernsey cows kept at the station. The data reported illustx'ate 



