May, 1912.] INHERITANCE OF HORNS IN SHEEP. 23 



evidence that at some time in her life she has produced, mated 

 with a hornless ram, a simplex horned male offspring. Where 

 doubt in the least exists I have given both the simplex and pure 

 hornless formulae. 



The data, derived from the 1912 lambs, may, perhaps, not be 

 considered pertinent or of sufficient importance to be included 

 in this paper. However, another twelve months will have to 

 pass before the horns are large enough to make accurate meas- 

 urements. I think I have determined the condition of their 

 horns correctl3 r , although I am free to admit that I may find 

 myself : mistaken in some cases. I have designated what I 

 thought was a simplex horn as "scur" and duplex as "horn." 



This bulletin is written merely to review and present what 

 data have already been obtained on horns in sheep in our breeding 

 investigations with these animals at this Station. It is not 

 intended as an ultimate effort in this regard, for we must verify 

 our results by making still further crosses. Our 1912 crop of 

 lambs will provide much valuable evidence. I include in this 

 paper a preliminary estimate of the condition of their horns. 

 However, since the oldest is five months and the youngest only 

 two months, I cannot accurately draw conclusions as to what sort 

 of horns they may eventually produce. I think, nevertheless, 

 that, from the experience I have necessarily gained in guaging 

 the size of horns, " my approximation in most cases will prove 

 correct. Bulletins on the inheritance of other characters in 

 sheep will be shortly published. The work progresses slowly as 

 is the case with breeding investigations with all large animals, 

 since it is greatly retarded by the inability to breed ewe lambs and 

 obtain strong, vigorous offspring. 



In conclusion I wish to pay tribute to the kindly advice and 

 aid Dr. C. B. Davenport, Director of the Station for Experimental 

 Evolution, Carnegie Institution of Washington, Cold Spring- 

 Harbor, L. I., has extended to me in this work at all times. 



