GUINEA-PIGEONS CROSSED WITH COMMON PIGEONS. 91 



One would wish to know what the reciprocal of this cross ( c? common x 9 

 guinea) would show. Only a single mating of this sort is recorded, and from this 

 but a single clutch of eggs was obtained. The data are : 



cf C. domestics; black with chequers. A 1. 5/27/10; dead 3 days after hatching. 



9 C. guinea (10); dead 6/22/10 A 2. 5/29/10; no devoopment. (P6) 



Matings and Back-Crosses of Guinea /////>/ -ids. In the mutiny and back-crossing 

 of guinea-homer hybrids many of the fertility and longevity features of the 

 primary cross reappear low fertility, seasonal and individual differences of fer- 

 tility, and a shortened life-term of the offspring. Xeverthelos. this term of life is 

 here an advance over the longevity of the primary cross, where, however, the life- 

 term was extremely short. 



Three matings involving 4 individuals of the second generation guinea hybrids 

 (i guinea, J homer) were made. The sires of the first two matings \\-ere brothers. 

 Two were mated back to homers. The results, placed in table 69, slum- low fer- 

 tility for the pair of inbred secondary hybrids, but fair fertility and perhaps longer 

 life-terms than were obtained from the primary hybrids. Two birds from sec- 

 ondary hybrids lived for 27 months, one lived 32 months. This seems to be near the 

 extreme limit of life of these hybrids from species whose individuals usually live 

 probably 5 to 15 years. 



One additional point is indicated by the result of the matings of the primary 

 hybrids, namely, that the males seem more fertile in the back-cross than are the 

 females. Three of each were tested with homers. From all the matings of such 

 males eggs (9) were hatched. Not one egg from the pairing of female primary 

 hybrids with male homers was hatched; only 3 of their germs showed any fertility, 

 and there was a minimum of growth in these a "circle of blood," a "little devel- 

 opment," and again a "little development." 



TABLE 63. 



Scries I. 

 cf C. guinea (1) ; escaped April 1904. 



9 C. tabeilarME 2) ; 8/24/99. 

 A 1. 4/26/00; no development. 

 A 2. 4/28/00; dead 3 hours after hatching (partly helped from shell). 



B 1. 5/24; dead 24 hours after hatching (partly helped from shell). 

 B 2. 5/26; no development. 



C. 6/5; data later rejected (by the author). cfF 1. 10/24; dead 18 days after hatching. 1 



F 2. 10/26; no development. 



D 1. 6/19; no development. Gl. 11 20; no development. 



D 2. 6/21; dead at 9 days after hatching. d"G2. 11/22: dead 11 days after hutching. 1 



El. 8/2; no development. II 1. 1J :!((; tin development. 



K 2. 8/4; no development. II L 1 . i i 01; no development. 



I 1. 2/15/01; no development. K 1. 4/5; no development. 



I 'J. 2/17/01; no development. K 2. 4/7; "formed only a circle of blond." 



?J 1. 3/4; dead, 19 days after hatching. 3 L 1. 4/20; no development. 



J 2. 3/6; no development. L 2. 4/22; dead 10 days after hatching. 4 



(G 5, A 14) 



1 " F 1 remained healthy and strong, and I was greatly surprised to find it dead on the morning < 1 can not 

 imagine the cause unless some organic defect I hut appeared quite suddenly as a result of the development, and not of disease." 



2 "The bird did well until the morning of Dec. '2'2, I'.tOO, when I noticed the vent soiled with a greenish discharge, and 

 concluded the bird was fated to die soon. I gave it a tonic tablet, and watched it. It grew worse rapidly and at 10 o'clock 

 I found it dead." 



3 "The bird appeared perfectly well the day before he died and was well fed. * * * The sex = ? I could not discover 

 any sexual organs." 



4 "On the evening of May Is I noticed the bird was wet about the anus. This watery discharge, in some cases greenish, 

 is a sure precursor of death." 



