Allgemeine Biologie und Entwickelungslehre. 23 



Rommel (^ gives a summary for breeding work of the external characters 

 of some of the commoner domestic, pure-bred varieties of Equus, Bos, 

 Sus, and Ovis. 



Spillmanf 1 ) gives further detailed data regarding the inheritance of the 

 horned and polled character in Bos [s. Bericht f. 1905 A. Biol. p 19]. 

 Spillman( 2 ) discusses the inheritance of coat color in Sus and presents re- 

 sults which indicate that white coat color is dominant over red. Red in turn 

 tends to be dominant over black, though the dominance il almost never com- 

 plete. 



Marshall presents statistics and a discussion of the effect of environmental 

 influences on fertility in Ovis. From data from 40 flocks it is found that 

 among flocks which have undergone a process of artificial stimulation (by 

 better feeding) during the sexual period the percentage of lambs is, as a rule, 

 larger than in flocks where there is no special feeding. Further the percen- 

 tage of barren Q Q m these specially fed flocks is relatively low. Finally 

 "it would appear that the artificial feeding exercises a stimulating influence 

 over the secretory activity of the ovaries" [thus hastening forward the sexual 

 season], "while at the same time causing the Graafian follicles to mature more 

 rapidly and a larger number to discharge during the earlier oestrous periods 

 in the sexual season". 



Barrington & Pearson present a detailed study of the inheritance of horn 

 characters and coat color in the shorthorn breed of -Bos, using in the main 

 stud-book records. So-called "blue-grey" cattle are as a rule produced by 

 crossing a black, polled Galloway cow with a white shorthorn bull. It is found 

 that even though the black and white individuals are from pure bred races 

 the hybrids are not homogeneous, but in some cases show color which was 

 not present in either of the parents (contrary to Mendelian expectation). If 

 the hybrid individuals are crossed back on either parent stock more segregation 

 appears. Red coat color sometimes appears in the offspring of such crosses. 

 The polled or horn characters are not found to be inherited according to Men- 

 del's law when individuals of pure bred races are crossed. Cross breeding of 

 the various color types (red, red with a little white, red and white, roan, and 

 white) does not lead to the expected Mendelian ratios among the offspring. 

 Treating the data biornetrically the results for parental and further ancestral 

 inheritance back to the great-great-grandparental are found to be in accord 

 with Galton's "law of ancestral inheritance", as determined from other forms 

 of life. The intensity of resemblance between individual and ancestor is shown 

 to diminish in a geometrical ratio the farther back the ancestry is taken. There 

 is a perceptible weakening of the intensity of resemblance with every change 

 of sex in the ancestral series. Collateral (fraternal) resemblance in shorthorns 

 is found to be of about the same degree of intensity as has been found in 

 other forms. 



Heron, dealing with family records for Homo and studbook records for Equus, 

 finds that there is no sensible inheritance of sex in these species. "The per- 

 sistent and sensible differences from .5 which occur in various races for the 

 sex-ratio are therefore not racial in the sense that they are an inherited 

 characteristic of the race; they must be in some manner associated with en- 

 vironment, nutrition, or habit". - - Woods dealing with data from Behr's "Genea- 

 logie" reaches the same conclusion that there is no inheritance of sex in Homo. 



