_>1 1MIKH1TANCK, FERTILITY, AM) SEX IN PIGEONS. 



incut, and one of these was strikingly abnormal, having rudimentary legs with 

 only two front toes, and with abnormal nostril; 9 young were hatched. One lived 

 long nearly 10 years; 4 died in less than 2 weeks. 



The second and third mat ings (tabeUaria x orientalis, 12 and 31) supply 23 

 tots of value (table 2), though incubation was not perfect in 5 or 6 of these; 4 did 

 not begin development (2 possibly from poor incubation); 7 developed, but 

 failed to hatch minst of them from poor incubation); 12 hatched, 1 lived nearly 

 :> years, - others of uncertain life-term but probably of 2 to 4 years, while 9 died 

 in' less than :> weeks after hatching; 1 of these latter birds had deformed legs. 



A fourth pair dnhcllaria x orientalis, 29) of more mature birds that were worked 

 vigorously at egg-production gave perceptibly better results (table 3). The 

 term of life of their offspring is noticeably increased. It is nevertheless quite clear 

 that the feat ures common to a cross of widely separated species are present. Tests 

 were made on 1!) eggs; 2 did not begin development, 2 others developed but were 

 deserted, embryos were produced in 4, 11 hatched. One of the offspring lived 

 more than (i years, while 4 others lived from 2 to 3 years; 4 died within 3 weeks of 

 hatching, and 2 of these were deformed. 



Pair") (tiffin /.s x orientalis, 2) yielded still better results. The female of this 

 pair was remarkable for the high degree of fertility of her eggs in other matings 

 also, and for having lived in captivity for more than 15 years. She was paired 

 with three different common pigeons, and was later mated for a term of 7 years 

 with a male of her own species. In the twelfth and thirteenth years of her captivity, 

 and when mated to her son, she produced "mutant" offspring, noted at the end 

 of this chapter and treated more fully in Chapter y. Of her fertility while mated 

 with the first of the three common pigeons under consideration we may note that 

 all of the (i eggs tested were hatched (table 4), and that the life-term of the offspring 

 was probably longer than has been observed in the preceding families. Here, too, 

 where fertility and longevity are less narrowly limited, a female (?) deformed, 

 and having a very rndintciilttri/ ovary is found among the offspring. Still another 

 of this family -the clutch-mate 3 of the deformed female (?) also had deformed 

 legs and died two weeks after hatching. One of the hybrids from this cross is 

 represented in pi. 35. 



A male homer (('. Ittbellaria, 1) which will later be noted as a remarkably fertile 

 bird (fertile with .S7. risoria) was given to the above T. orientalis female in the 

 autumn immediately after the production of the last-mentioned series of fertile 

 . This pair ((>) was then made to produce eggs as rapidly as possible. This 

 gave the result best made clear by reference to table 4. The extreme end of the 

 season yielded f> eggs incapable of beginning development. Only 4 eggs hatched 

 from 11 adequate tests; 1 of the young was deformed, and 1 full-term embryo was 

 also probably deformed. From pair 7 (('. nffinix? x orirntnlix 2) only 4 eggs were 

 obtained; these immediately followed the "Overwork" period of the preceding 

 pair. Two were tested, though imperfectly; one produced an embryo, the other 

 did not. 



Pair S was formed two years later by mating this same female with an immature 

 male (('. <i<hni*l<i ? 11 1). The pair was overworked. They supplied 21 tests with 



' Tlir term "clutcli" is applied to the two egjrN laid al one nesting period. The second egg is laid 40 to 48 hours 

 after the lirM. I'articulars for the various species are given in Volume 111. 



