278 MAINE AGRICULTURAI, EIXPERIMENT STATION. igi2.. 



1906, 1907 and 1910) it appears that of the 10 young born 

 from these four pregnancies, 5 were males and 5 were appar- 

 ently females. That is to say. they were females so far as 

 external sexual characters were concerned. It is a curious fact 

 that in all of the single births which this cow had the offspring 

 were females. Whether this is merely a coincidence or has 

 some deeper significance with reference to sex determination 

 is not apparent. 



(c) During the breeding history of this cow there has ap- 

 parently been a steady increase in her rate of fecundit3^ The 

 first three pregnancies resulted in single off'spring, then came 

 in succession two pairs of twins followed by triplets, and then, 

 with a single pregnancy between another set of triplets. This 

 would seem to indicate that as this cow is successively bred her 

 tendency towards multiple gestation comes more and more into 

 expression. 



(d) The breeding history of this cow indicates that she has 

 a definite and innate constitutional tendency towards multiple 

 gestation, not due primarily to the action of external circum- 

 stances. If a normally uniparous animal has multiple births 

 more than two or three times out of every ten births it is good 

 evidence that the occurrence of such multiple gestation is not 

 fortuitous but rests on an innate physiological tendency of the 

 individual. In the present case there are four multiple births 

 out of eight pregnancies. If there had been triplets but once 

 in the breeding history of this cow, the occurrence might very 

 well liave been taken to be accidental. It is apparent, however, 

 that for some reason this cow possesses a definite tendency to 

 bear more than one young per birth. The ten:^ency towards 

 multiple gestation in this case cannot be due to rich or forced 

 feeding. Neither of the two men who have owned the cow 

 during her life have ever fed her heavy or rich rations. On 

 the contrary she has been nourished during the greater part 

 of her life on a relatively small amount of grain and a large 

 amount of roughage. 



(e) It is interesting to note that the sire of the last set of 

 triplets (these born in 1910) was the male member of the for- 

 mer set of triplets borne by the same cow. It is in many ways 



