158 INHERITANCE, FERTILITY, AND SI.X IN PIGEOXS. 



is doubtless partly accounted for by the fact that in each case one parent died 

 at or near the close of the breeding period. From the latter cross a single bird 

 matured. This male (F-0), though of general dark color, was a true intermediate 

 to his ring-Surate parents in color and color-pattern characteristics, as is well 

 shown in pi. 25. He was mated to 5 different females, as indicated in tables 152 

 and 153. When 4 to 5 years old and mated to a St. alba, half of the eggs produced 

 were hatched; at 7 to 8 years old, with another alba, only 7 of 19 eggs were hatched. 

 With an dlba-humilis hybrid a group elsewhere noted to be of low fertility 

 there was no trace of development in any of 4 tests. With St. risoria 1 young 

 hatched from 2 tests; and with St. humilis 1 young hatched from 6 tests. It is 

 clear therefore, that this bigeneric hybrid did not possess full fertility with 2 of 

 the 3 parental species, nor with a third one related to them. 



One of the offspring of the above-described male (F-O) and a St. alba female is 

 shown in color in pi. 26. Its color is several grades lighter than that of the 

 sire. Some of this fraternity were, however, darker than this individual. There 

 was in this family no limitation of color by sex; there were darker and lighter males, 

 as well as darker and lighter females. The pale-colored male just referred to in 

 the plate was crossed with a humilis-risoria hybrid (table 154), which was darker 

 than the mate in color, and with this bird threw several "white" young (5 of 13), 

 in addition to two or three different darker shades of young. One of the darker of 

 these dark offspring is reproduced in pi. 26. This interesting bird is a hybrid of 4 

 species belonging to two genera. 



We may now return to a consideration of other features of the breeding data. 

 The results from the mating of the male (F-O) with the pure white rings deserve a 

 further word. This male was I alba, i risoria, i suratensis, and sired 16 young 

 from the two matings with female St. alba; there were, however, no white offspring. 

 The tendency toward suratensis color in these youn-g is clear in about 9 cases; a 

 tendency toward risoria is shown in about 7 individuals. In this case, as previ- 

 ously noted with orientalis, risoria, and humilis, the species alba, when used as dam, 

 only slightly modifies the color of the young of the Fi generation. 



In the first mating of this same male with St. alba (table 152) it is clear that the 

 late autumn is the period of least developmental capacity for the germs, and that 



EXPLANATION OF PLATE 26. 



A. Adult male complex hybrid (TH 7). Hatched Apr. 19, 1905. Six-tenths natural size. Hayashi 



del., July 1906. 



Four species are represented in this hybrid: St. alba has entered three times ( = 5/16). XI. risoria has entered 

 three times ( = 5/10). Spil. surnti/ixits has entered once ( 2/l(i). St. humilis has entered once ( = 4/16). The 

 sire is shown in color below, fig. B; neck-mark in pi. 34. The dam was a St. humilis x St. risoria hybrid (O 2) of 

 dark color. 



The size of TH 7 is about the same as that of St. risoria x St. It inn it is hybrids, or a trifle smaller. The color 

 strongly resembles a male SI. risoria x St. kuiiiilis hybrid, but with a weak isitnik'itsis mark (mesial stripe), which is 

 about the same as that of the first risoria x surali'itxia hybrid. The mesial stripes of the sire (T 1) are very faint in 

 this bird; this is caused not by a ilircrt effect on the region of the mark, but by a strengthening of the pigmentation 

 as a whole. The neck-mark is now practically that of 14/16 of t.he ancestry. 



B. Adult male Streptopelia risoria (1/8) Spilopelia suratensis (1/4) Si. alba (5/8) hybrid (T 1). 



Hatched May 16, 1903. Six-tenths natural sixc. 



Sire, shown in color, pi. 25, fig. B. Dam, St. tdha (1902). 



Note another degree of "lightening" of the S-/>il. Ktiruli tixi* color, through a second ring-dove cross. The area 

 of the neck-mark is further limited, and once more approaches tin- proportions found in the ring-dove. A slight 

 division of the feather-tip persists. 



