THE KANSAS UNIVERSITY 

 SCIENCE BULLETIN. 



Vol. X, No. 15.] January, 1917. [vl^xl.xo'i! 



A Mule and a Horse as Twins, and the Inheritance 



of Twinning. 



W. REES BREBNER ROBERTSON, 



University of Kansas. 



THIS occurred on the farm of George E. Loy, of Barnard, 

 Kan., June 9, 1913. On hearing of the case, in March, 

 1916, I looked it up and found, from the testimony of Mr. Loy 

 and his family and neighbors, and that of the photographers 

 who took the pictures and from my own observation, that the 

 following are the facts concerned. 



In 1912, the dam (III9), just ten minutes before being bred 

 to the ass stallion (III7), had been bred to a young three-year- 

 old horse stallion (IIIo), which was being used as a part of 

 the technique sometimes thought to be necessary in securing 

 the fecundation of the female horse by the male ass. In such 

 cases fertilization is expected from the second sire. In this 

 instance, however, there resulted twins, one of which was a 

 male horse, the other a female mule. 



The case in itself was of sufficient interest, fortunately, to 

 be photographed at the time by the local photographer, who 

 sold the pictures (fig. 1) at fifteen cents apiece. Photographs 

 were also taken later by the district school teacher (figs. 2, 3 

 and 5). Photographs 4 and 6 were taken by myself. Un- 

 fortunately, the mare (IIIo) had died of old age during the 

 wintertime preceding my visit, and the horse foal (IVio) had 

 died of exposure and poor feed the winter of 1914-'15 at eight- 

 een months of age. But in spite of these discouragements, the 

 data given by Mr. Loy and his children and by his neighbors 

 checked up in every way so well with the evidence afforded by 

 the photographers, and with what I have been able to observe 

 myself, that it seems worth while to put the case on record. 



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