164 Scientific Proceedings , Roijal Dublin Society. 



The presence of scurs among liornless cattle has already been referred 

 to. These are mere loose epidermal growths, sometimes an inoli or two 



Old Egyptian hornless Cattle. 



long attached to the skin where the liorns ought to be. But, tliough the 

 skull is often full and square in the animal with scurs, there is no developed 

 core or bony outgrowth beneath the sours. Scurs are fairly common among 

 tlie Irish Maoiles, but tliey have been almost entirely bred out among the other 

 hornless breeds. In a mixed herd of horned and hornless cattle where sours 

 are common this bony outgrowth is used to tell whether tlie calves are going 

 to have horns or not. Those with fixed immovable outgrowths will liave 

 horns ; those witli slack movable scurs will have none. These phenomena 

 raise a series of questions wliich of course we cannot decide: What are 

 scurs ? What are tlieir functions ? They occur independently of horns. 

 Have they any bearing upon the origin of horns or upon the origin of 

 hornlessness ? Did the growtli of the bone of the horn at one time cause 

 a sympatlietic, perhaps concomitant, growth of epidermal born ? or are 

 the scurs merely a legacy left by the horned upon the hornless cattle they 

 crossed, and do they appear because tlie epidermis is willing to perform 

 its part while the bone below refuses ? 



