No. 62,1] PIXK-EYKJ) SKLF WHITE (,V I X EA^l'IGS 125 



Breeding Operations 



As previously stated there were three animals with 

 which to begin breeding operations in the production of 

 the synthetic pink-eyed self whites. These were two 

 non-yellow agoutis, J* 360.1 and $361.1, and a pink-eyed 

 non-yellow tortoise, $363.1. By various test matings 

 these were proven to be of the following gametic com- 

 positions: J* 360.1, AaPpCrCrC^'e^^;' $361.1, AaPPCCe^e^ 

 and ? 363.1, aappCrCre^'e^. It will be seen that all 

 three were homozygous for c^', the factcn- for the partial 

 extension of black or chocolate. ( >ii Ihis account it would 

 be impossible by mating tlie aiiliiials toucllici- to produce 

 the pink-eyed self whites since the tlesiied niiimals must 

 lack the extension factor and therefore l)e ee. 



What seemed the best method of procedure was to 

 mate $363.1 {ppCCrP^e^) to a self red (PPCCec), and 

 then to inbreed the F,V (PpCCc'r). Thi-e all Looked 

 like ordinary tortoises. Since this was a t !-I-h\l)rid 

 cross and since tlie desii'ed aiiiinals were to lie homo- 

 zygous recessives, it wouh! iheoret ieall\- he necessary to 

 have(;4otr-],rinu lor the pr.xhietion of of thi'.h-ir.Ml 

 t>pe. Thi. ]Moxed to h,^ a xerx ^h.Nv pKu-e.. aii.l ua^ 

 filially disrai-ded in favor of other less nu'thodical rat- 

 ings, which were more rapid in their I'esults. Tiie most 

 successful will be described in some detail. 



A heterozygous tortoise (^572.1, of the eompo-ition 

 PpCCe^e obtained by mating ^"360.1 to a self re.l. was 

 mated to a yellow-and-white female. iVl\K'-K carr\inu- al- 

 binism iPPCCnCc). One of theii- otrsi)rin.u-. -s-HM 

 (Fig. 2), was at first mistaken for an albino, hut more 

 careful examination proved him to In' a dai'K-e\e(l mm- 

 extended non-yellow. The reason for niistakinu' him for 

 an albino was that he did not can-\ hlaek (//i. His 



