TWINNING IN RUMINANTS 97 



a blind end, a two-horned uterus, testicles nearly as 

 large as those of a bull, and no ovaries. Seminal 

 vesicles opened into the vagina, but there were no \'asa 

 deferentia. A clitoris was present. This animal was 

 preponderatingly male, but showed organs of both sexes. 

 The third (three or four years old) was more like a heifer. 

 There was the beginning of a vagina open as far as 

 the urethra, a two-horned uterus, and paired ovaries. 

 But there were also seminal vesicles and part of the vasa 

 deferentia. This individual was predominantly female, 

 but also had organs of both sexes (a hermaphrodite). 

 Hunter's view that the freemartin is a transverse 

 hermaphrodite with a varying predominance of the two 

 sexes is the classical one, and it went unchallenged for 

 some time. 



The most extensive collection of data up to that of 

 Lillie was made by Numan,' a Dutch investigator, whose 

 paper, together with an atlas of illustrations, I have had 

 the opportunity of looking over. This monograph has 

 been translated into French and from the French into 

 German by Spiegelberg. In the course of these transla- 

 tions some accuracy has been lost. Hart gives what 

 proves to be a very poor and inaccurate translation of a 

 summary of Numan's findings. In brief, it may be said 

 that Numan claims to have evidence of the following 

 kinds of opposite-sexed twins in cattle: (i) normal 

 male with sterile female (freemartin) ; this is much the 

 commonest type; (2) normal male with normal female; 

 this is a rare type; (3) normal female with sterile male; 

 this is an extremely rare type and is based on second- 

 hand or hearsay information. Numan pictures both 



I A. Numan. Utrecht: Van der Monde, 1843. 



