SUPPLEMENTARY NOTES ON TWINS IN CATTLE. 59 



it is possible that in the present case the gonad would have grown 

 considerably. But it could not have passed out of the body cavity, 

 for the gubernacula did not enter the body wall in this case. And 

 it is impossible that a male type of external organs could have 

 developed in this case, for the definitive female type was already 

 formed. 



Cases at the other extreme from the present one also throw 

 some doubt on the merely quantitative explanation of the degree 

 of intersexuality. I refer to cases where the vascular intercon- 

 nection is very delicate. One case of this kind, not previously 

 reported, is especially striking (No. 81). In this case I at first 

 doubted the existence of an actual arterial anastomosis, for the 

 injection was not very successful. A careful examination, how- 

 ever, showed an exceedingly delicate artery from the male side 

 passing far into the territory of the female chorion and there ap- 

 parently anastomosing with an artery from the female. The re- 

 productive system of the free-martin in this case (stage of 14 cm.) 

 was typically intersexual (Fig. 4) and similar in all essential re- 

 spects to the case shown in Fig. 15 of my former paper: gonads 

 reduced, ducts of the male type with rudiments of the cornua uteri 

 persisting, however, gubernacula present, etc. Indeed, this case is 

 certainly more modified than No. 78. 



Keller and Tandler (1916) describe a case in which the vascular 

 arrangements found seemed inadequate to account for the typically 

 deformed condition of the reproductive organs of the free-martin. 

 In this case they state that no strong vascular anastomoses were 

 demonstrable, nevertheless the female exhibited the typical mal- 

 formation of the reproductive system. They add that a welt-like 

 connection similar to that which usually carries the connecting 

 vessels was found between the main vascular trunks on the two 

 sides, but that it possessed no lumen. They consider this as point- 

 ing toward the possibility of an earlier typical connection that 

 became interrupted secondarily. 



All free-martins that have been described depart very widely 

 from the female anatomical plan, and also very widely from that 

 of the male. If we were to imagine a sex scale of, say, twenty 

 points, in which points 1, 2, and 3 on the left include the normal 

 female range and 18, 19, and 20 on the right the normal male 



