EXPERIMENT STATION RECORD. 769 



ANIMAL PRODUCTION. 



The principles of Mendelian inheritance and their cytological foundation, 

 F. Pf;ciiouTRE {Rev. G6n. Sci., 23 {1912), No. 16, pp. 613-623, figs. 3).— This is 

 a review unci critical discussion of Meudelism, with si^ecial reference to the 

 function of the chromosomes. 



Gametic coupling as a cause of correlations, G. X. Collins {Amcr. Xat., 

 J,6 {1012), No. 5.30, pp. 560-500).— It is pointed out that the theory that the 

 various degrees of association in gametic coupling fall into a regular series, 

 represented by powers of two, has been accepted without adequate analysis of 

 data. To overcome the lack of a standard for making comparisons the author 

 advocates the use of Yule's coefficient of association.* 



From studies of maize and other hybrids the author finds that in several 

 cases correlations are reversible, depending on the way the characters were com- 

 bined in the parents. This fact makes it necessary to assume that characters 

 which at one time atti'act each other, at otlier times exhibit repulsion. 



The general conclusion reached is that associations between characters, like 

 the appearance of single characters, may arise at different stages in the ontog- 

 eny of the individual. 



Another view of sex-limited inheritance, R. M. Strong (Science, n. ,ser.. 36 

 {1012), No. 927, pp. Ji.'i3-/f.'f5). — In the first generation of crosses with white 

 ring doves {Turtur albn) and blond ring doves (T. riftorius) the hybrids re- 

 sembled one parent or the other in equal numbers. The blond hybrids were 

 mostly males and the white hybrids were all females. When these latter were 

 crossed back on white males only white otTsi)rlng were obtained, and are there- 

 fore so-called extracted recessives. An explanation is given to account for these 

 results without assuming that the male is homozygous for sex and the female 

 heterozygous, or that a spurious allelomorphism may exist with the consequence 

 that certain sex and somatic f.nctors may not be present in the same gamete. 



Another sex-limited character, E. N. Wentworth (Science, n. ser., 35 

 (1912). No. 013, p. 986). — The rudimentary mammte located on the scrotum of 

 the male and on the inside of the thigh of the female swine appear to be a case 

 of sex-limited inheritance in a manner similar to the inheritance of the horns 

 in Wood's crosses in sheep (E. S. R., 22, p. 378). 



The genetic factors in the development of the house mouse which in- 

 fluence the coat color, A. L. Hagedoorn (Ztsclir. Induktive Ahstani. ii. Verer- 

 hungslehre, 6 (1912), No. 3, pp. 97-136, pi. l).—\ detailed study of the in- 

 heritance of coat color in over 6,000 animals. 



The sex ratio in hybrid rats, Hixen D. King [Biol. Bui. Mar. Biol. Lab. 

 Woods Hole. 21 (1011), No. 2, pp. 10.'f-112).— This reports data of experiments 

 with hybrid, rats in which the excess of mayes was so far beyond the limits of nor- 

 mal variation that it appears that hybridizing altered the sex ration to an appre- 

 ciable extent. This is in agreement with the results obtained by other observers. 



Studies in the experimental analysis of sex. — IX, On spermatogenesis and 

 the formation of giant spermatozoa in hybrid pigeons, G. Smith (Quart. 

 Jour. Micros. Sci., n. scr., 58 (1912), No. 229, pp. 150-170, pi. i).— -These are 

 studies of normal male pigeons and doves and 3 male hybrids produced by the 

 mating of a male pigeon with a female domestic dove. As a rule the findings 

 of Guyer ^ were confirmed. The following conclusions were drawn : 



"The ripe spermatozoa of the hybrids, which were present in large quan- 

 tities, besides showing in certain cases structural abnormalities, were on the 

 average twice as large as the normal spermatozoa of either parental type. 



"Phil. Trans. Roy. Soc. London. Ser. A, 194 (1900 1, pp. 257-319. 



»Diss., Univ. Chicago, 1900; Biol. Bml., 16 (1909), p. 193; Anat. Anz., 34 (1909), 

 pp. 502, 573. 



