i8 



ORIGIN OF A POLYDACTYLOUS RACE OF GUINEA-PIGS. 



The original polydactylous guinea-pig (<$ 23, table i, p. 18), was born to 

 parents of almost unknown ancestry, but certainly not closely related to 

 each other. The mother, a spotted animal ($51) produced no other poly- 

 dactylous offspring, though she bore in all thirty young. But the father 

 ((^4i.i a ), who sired in all one hundred and forty-seven young, had five 

 other polydactylous offspring. These were all, except one,* borne by females 

 descended from himself, and that one was borne by his half-sister (J42.i a ), 

 so that it seems certain that the polydactylous character came in every case 

 from the same individual, 41. i a . A son of $ 41.1* viz, $ 243 (table i) 

 whose mother was half-sister to <$ 41.1% produced, like his father, a certain 

 number (five) of polydactylous offspring, which were used in building up 

 the polydactylous race. 



TABLE I. Ancestry of the various males used in building up the polydactylous race. 

 The character of the extra-toe is indicated by letters following the numeral which designates each individual- 

 These letters signify : G, good ; F, fair; P, poor; N, normal, i. e., three-toed. Read downward. 



9*1 3f*. Q4^ 



I I 



d"/V/V 



63046-GG. 



* In an earlier paper (Castle, 105) this exception was inadvertently overlooked, 

 and the total number of young sired by c?4M a was given as 139 instead of 147. 



