334 



Scientific Proceedings, Royal Dublin Society. 



to the tenth volume, in the hope that errors incidental to the earlier volumes 

 of stud-books might be eliminated. The results are as follows : — 



Selected Matings in vols. i. to x. of the Shire Stud-book. 



It will be seen that the figures in tliis Table are practically a re-eclio of 

 those in the former. The relations of black to chestnut and brown to bay 

 are no clearer. Remembering the errors of description to which stud-books 

 are liable, black, brown, and bay, when bred to their own colours, seem to 

 breed with regularity ; but black is disturbed by the intrusion of chestnut, 

 bay by black, and brown by black and chestnut. 



A similar and larger collection of data from the Clydesdale stud-book, 

 which was next resorted to, gave almost identical results and left us no 

 farther forward. 



But a deeper search into this book showed a possible cause of the 

 disturbances referred to a few lines back. Among Clydesdales, breeding 

 stock are usually entered in the stud-book twice : first as foals and after- 

 wards when they themselves have foals to be entered ; and their colours are 

 usually mentioned both times. It was found that the colours of a good 

 many animals were not the same at the second as at the first entering. 

 The changes were not only from bay to brown or from brown to bay ; but 

 almost as many were from brown to black or black to brown. There was 

 also a considerable number of changes involving chestnut and brown and 

 chestnut and bay. 



We were thus driven to the Thoroughbred stud-book, which had been 

 avoided so far because of the large amount of tedious labour involved 

 in ascertaining sires' and dams' colours. Thoroughbred colts are not entered 

 a second time unless to make corrections ; and the colours of fillies when they 

 re-appear with their progeny have been given only in the last three volumes. 

 For our purpose. Thoroughbreds have an advantage over Clydesdales and 



