134 INHERITANCE, FERTILITY, AM) SKX IN PIGEONS. 



eggs tested were hatched. But the homer here used as sire was a (Horn. 1) bird 

 whose remarkably high fertility has already been described in Chapter IX. It will 

 here be noted, however, that the life-term of the offspring is quite short and that 

 the young die suddenly without previous signs of illness. 



From 34 tested eggs of a female common pigeon of unknown origin but con- 

 sidered a homer, mated to a male alba-riaoria hybrid, 6 young were hatched, as shown 

 in table 116. It is notable that the 2 young from this cross whose sex was recorded 

 were classed as females (there is no record of autopsy of either of these birds; see 

 below). This case would seem to constitute a violation of the rule that males 

 only arise from family crosses unless the possible hybridization of the female parent 

 be considered of importance. During 1897, when this sire was immature, 20 of 

 the above-mentioned 34 eggs were laid, and only 2 of these showed even the 

 beginnings of development (7 to 10 day embryos). 



Later 91 eggs of this same stray common pigeon (Horn. 4) were laid while mated 

 to another male F 2 hybrid (alba-risoria x risoria-alba, E 2}. The result is fully 

 given in table 117. Only 1 1 birds were hatched from this large number of eggs. The 

 seasonal distribution of color in these offspring is of some interest. 3 birds from the 

 early and best part of the season were quite dark ("much brown"); 3 birds from 

 late in the season were of light color, 1 being "light" and 2 "very light." There 

 was 1 bird recorded as a female among these young. 



From these two matings of hybrid ring-dove males with a stray female homer (?), 

 it has been noted that both male and female young were apparently obtained; the 

 female parent was, however, a "stray bird," and although a homer in appearance, 

 may have been a hybrid from a cross with at least another domestic variety. The 

 question of greater importance is, as briefly indicated at the beginning of this 

 chapter, were these offspring birds really females? Neither of them seems to have 

 laid eggs. Two of the three copulated as females and accepted males as mates, but 

 during more than 12 months of such mating were positively known to have 

 produced no eggs. The editor is convinced that the author classified at least 

 2 of these 3 birds on the basis of their sex-behavior (they were obtained at the 

 beginning of his hybridization studies), and that, in the light of later work, it 

 is very questionable whether these birds bore ovaries. The term of life of the 

 offspring of these two matings is not long, and 2 (or 3) of the 17 young were 

 notably deformed. 



In the final mating of this series the male is a bigeneric hybrid (T. orientalis x 

 81. risoria) and the female is a homer. The very restricted fertility of the pair is 

 made clear by reference to table 118. It is when fertility is very low, as in this case, 

 that the differences between the developmental capacities of various germs are best 

 shown, and here, too, that "seasonal" differences are the more readily detected. 

 The following statement is found concerning the results of this mating: 



Male OS 1 and the female homer again have developing eggs (March 19, 1909). They 

 previously hatched 1 young at the beginning of the season (see record). Here is another 

 proof of greater strength at the start, at the first of the season. 



On July 13 (1909), OS 1 and the homer again have 2 eggs fertilized, but fail to carry 

 out development. These two eggs, laid July 1 and 3, furnish a good case of weakness of 

 development in the egg. One developed for 5 to 6 days. The other developed up to making 

 the first puncture of the shell on July 18. The puncture was open for a space of about 3 to 



