ALTERNATIVE INHERITANCE 



15 



principles. Hundreds of examples of this could be adduced from my 

 rearings, both from pure and crossed matings (with reference to larval 

 pattern) within the Italian Salmon race and to outbred matings with 

 various other races, as Bagdad, Istrian, Chinese White, etc., etc., 

 having larvae of white type. A few cases out of these hundreds will 

 suffice. In all of the scores of matings in the past five years within 

 the Italian Salmon race, testing the Mendelian behavior or relation in 

 inheritance of the two larval types, tiger-banded and white, the two 

 characters behaved in rigorous Mendelian manner, tiger-banded being 

 dominant, white recessive. Never did intergrades appear, never did 

 a tiger-band larva appear in a white X white mating, and wherever the 

 reared cross-bred lots were carried through in something like their full 

 strength the proportions of the two types called for by Mendelian 

 inheritance were closely approximated. 



In outbred matings, with races of white larval types, the results 

 may be summed as follows : 



Italian Salmon crossed with Bagdad. Tiger-band characteristic is 

 dominant in matings of tiger-band Italian Salmon larvae with Bagdad 

 larvae (always white). In second generation rearings from hybrid 

 matings the parental characters segregate according to Mendelian 

 proportions, in many cases the 3 to i proportions being almost exactly 

 followed. White larvae mated together either in F^ race crosses or in 

 F2 and succeeding hybrid generation crosses never produce a tiger-band 

 larva. Reciprocal crosses (as to sex) in both F^ and succeeding 

 generations behave similarly; i. e., show no dominancy of sex. 



Italian Salmon crossed with Istrian; Italian Salmon crossed with 

 Galbin Italiano ; Italian Salmon crossed with Chinese White, and other 

 crosses of Italian Salmon with white larva races. In these race crosses 

 tiger-bandedness of the larvae behaved regularly as a Mendelian domi- 

 nant and whiteness as a recessive, and the various familiar 3 to i, 2 to 

 I and I to I proportions dependent upon the assumed germ cell 

 character of the dominant-carrying member of the pair were all closely 

 approximated in the many lots bred. 



Patterned type. — The "patterned" type of larva (PI. I, fig. 4; PI, 

 III, figs. 3, 7) is shown characteristically by the Japanese White, Italian 

 White and certain other races. Although subject to considerable 

 fluctuating variation (see p. 43) it behaves in inheritance usually as 

 a unit characteristic and is alternative in transmission. It is recessive 

 to tiger-bandedness but dominant to whiteness. But it seems not to 

 be really a unit character in that in cross matings with tiger-bandedness 



