52 THE MENDEL JOURNAL 



hence Ayrshire, Ladas, and some other Derby winners 

 cannot be classified as stayers. In the table the 

 probable gametic composition of each stallion is 

 affixed, though it will be observed it does not always 

 coincide with his manifest somatic character ; that, of 

 course, is a familiar Mendelian phenomenon. 



Let us assume for the moment that the dark red 

 fibres, symbolised as R, and the pale red fibres, as P, 

 are represented in the germplasm by alternative unit 

 characters, and that neither factor in the body cells is 

 dominant. In these circumstances, granted that 

 sharp and clearly-defined segregation, both in the 

 sex and body cells, took place, we may conceive 

 theoretically that three possible somatic combinations 

 of the pale and red fibres would occur. They are 

 shown in the following table : — ■ 



Sprixters = pp. i.e., theoretically all their muscles are of the pale 

 variety. 



Intermediate = PR, i.e., theoretically their muscles are a mixture 

 of the red and pale varieties. 



Stayers = RR, i.e., theoretically their muscles are assumed to be 

 of the red variety. 



Nature of Mating. 



Parents. Result of Cross. OfiEspring. 



PP X PP = PP only. 



PP X PR = PP and PR in equal numbers. 



PPxRR== PR only. 



RR X RR = RR only. 



RR X PR = RR and PR in equal numbers. 



RR X PP = PR only. 



PR X PR = PP, PR, and RR in the ratio of 

 1:2:1. 



