396 FRANK R. LILLIE 



correspondingly reduced in a relative sense A\'ith the result that 

 the prominent arteries and veins become exclusively cotyledon- 

 ary with the single exception of the artery connecting the two 

 sides; and any intercotyledonary venous connections become 

 insignificant. 



It is an important question whether this condition persists 

 throughout foetal life, even though completely sterilizing effects 

 on the female reproductive system are produced by the stage of 

 7.5 cm., as we shall see in more detail in another section. The 

 question therefore relates to possible influences on later stages 

 of the female reproductive organs, and on the somatic characters 

 of both t\\ins. The latest stage that I have examined wdth 

 reference to this question was a pair of female t\\ins, 35.3 cm, 

 and 31.25 cm. in length respectively. The arterial connection 

 was even stronger than in earlier stages proportional to the 

 more advanced stage of development. There is no reason to 

 suppose that the connection is interrupted until birth, but the 

 actual observations have not been made. 



Thus the available records indicate a growth of the arterial 

 anastomosis throughout foetal life and a consequent duration of 

 action of the male hormones up to the time of birth. The possi- 

 bility exists that in certain cases the connection may be inter- 

 rupted at different stages of development; but so far no such 

 cases have appeared. In any event the decisive effects on the 

 reproductive system of the female are determined very early 

 and they are presumably irreversible in their character. 



Triplets occur rarely in cattle, and cases of eA'en more young at 

 a birth are on record. Unfortunately records of their breeding 

 history appear to be very rare. The only one that I have been 

 able to discover is given by Pearl ('12). In this case there were 

 two females and one male. The females were kept until they 

 were about three years old, but they never came in heat. They 

 were then killed, and ''The man that dressed them said that they 

 never would have bred. Neither uterus nor tubes were recog- 

 nized, but the vagina apparently ended at its anterior end as a 

 blind sac." Both were apparently sterile free-martins. The 

 male was put in service and got good calves. We have here. 



