76 



INHERITANCE IN GUINEA-PKJS. 



SB Block. A Mock consisting exclusively of very intense blacks. 

 So red or white Bpotting h;ls been observed among them. Unfortu- 

 nately it is a stock of low fortility, and could not be used much to 



advantage . 



/.Ml' gtodk.— This stock has for years consisted exclusively of very 

 intense blacks and very Booty albinos. The blacks occasionally show 

 i few red hairs or a small red patch. This has been an extremely 

 ful stock, among other thingB, furnishing albinos known to be geneti- 

 cally identical with blacks, except for the albino factor. (Race B of 



,r-tn< slock — This is a much-inbred stock, practically all the indi- 

 viduals of which show four good toes on the hind feet instead of the 

 normal three. This stock was developed by selection and inbreeding 

 by Professor ( !astle (Castle, 1906). Most of the individuals are a dull 

 black with dull red blotching and brindling and often with white spots. 

 Albinos appear quite frequently and reds much more rarely. 



Table 34. — Genetic formulae of stocks. 



/ n ih, tricolor stock the fur is typically a patchwork of red, white, and 

 black. Full-roughs, partial-roughs, and smooths occur among them. 

 The writer has used many guinea-pigs of very mongrel ancestry, which, 

 however, owe their partial rough coat to this stock. 



Tl i i picHmdrcn am and brown-eyed cream stocks have been selected 



for years for extreme dilution. The former stock consists exclusively 



of Bepias, Mack-eyed yellows and creams, and albinos. The latter 



siste exclusively of brown-eyed yellows and creams and albinos. 



C of Part I.) In the tables, these together are called dilute- 



Belection -tuck. 



Table :;t shows the Mcndelian factors affecting color and roughness 

 of fur which occur in each stock. Unanalyzed hereditary conditions 

 which affed color and roughness are also included, prefixed by the 

 symbol I. 2w and 2y. as has already been stated, mean hereditary 



