48 Journal of Agricultural Research voi. xv. no. i 



The polled character in these crosses occurs most frequently in the 

 females. In 7 offspring from matings of homed males with polled 

 females, 3 polled females were produced to i polled male; i male and i 

 female had scurs and i male had heavy horns. In the reciprocal cross 

 of polled male bred with horned female, i male was doubtfully recorded 

 as "loose scurs under the skin." He died before this could be checked. 

 Of the others, 7 females were polled, 3 males had solidly attached scurs, 

 6 had loose scurs, and i was horned. 



These data make it probable that sex has some influence on the 

 horned condition. The parallel with the case of sheep is of special 

 interest, for castration experiments by Wood and others {57) have 

 established the presence of a secretion by the testis which materially 

 aids the production of horns in this species. On the basis of this the 

 testis in the bull would be expected to secrete a hormone which would 

 produce horns with one dose of the horned genes, where two doses of 

 the homed gene would be required by the female. 



The parallel is still further emphasized by the variabiHty, both intra- 

 and inter-racially of the action of this secretion or hormone. Thus, 

 Crossbred 9 (PI. 4, A) at three years had scurs only, whereas Crossbred 

 21 at one year had heavy horns. For the case of sheep the work of 

 Arkell and Davenport (j) have shown a similar length of time necessary 

 for the action of the secretion in this species {see also 13). 



This variability in the action may be the explanation of the results 

 obtained by Lloyd-Jones and Eward (20), where, out of 78 offspring 

 of a Shorthorn bull to Galloway cows, they obtained only 6 scurred and 

 2 homed animals (see p. 45). Here it is conceivable that in this 

 cross the secretion may be small in amount or lacking as in some of 

 the merinos that Arkell bred. Such a lowered concentration or amount 

 of the secretion would explain the results, as without its aid to the 

 growth of horns the male offspring would be polled like the female, 

 and the results obtained by Lloyd -Jones and Eward would be expected. 

 This difference in the behavior within a species is still further empha- 

 sized by the work of Morgan {24) on the hen-feathered races of poultry. 

 In this case the hen-feathered character is known to vary all the way 

 between a strictly hen-feathered male to one of almost complete cock 

 plumage. This variability may also take place in the same bird of 

 the Campine race, owing to age or to a difference in the physiological 

 state of the bird. 



The position of cattle in the series of animals known to possess such 

 a secretion seems intermediate between that of reindeer and sheep, 

 since castration experiments on the horned breeds show no retarding 

 of the horn growth, although it does tend to make the horn longer and 

 more slender. 



