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 ($42.1*), 

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

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

 whose mother was half-sister to <$ 41. i a , 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. 



$41 3K. 042 



I I L I 



$51 



3 4 



1. t < 



d/V/V. 

 I 



I. A 



QI90 



Q46I-FN. gSte-QG. 67//-GG 



d/93-Fr. 



\ 



f> 768-GC. 



$635 -ff 



Q308- 



-r" 



3d09-GG. Q8IO-GG. 

 \ I 



3ll65-GG. 



$>8/6-GG. 



3/14-O-GN. 



O/^63GG 



63O46-GG. 



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

 and the total number of young sired by d'4i.i a was given as 139 instead of 147. 



