100 INHKKITAXCK, KKKTI LITY . AND SEX IN PIGEONS. 



barbs throwing some red and some gray offspring; the importance of these data 

 lies in the suggestion that these colors arise from the "weaker germs," and 

 in the evidence furnished by this group for the genetic non-equivalence of the two 

 eggs of Hie pigeon's clutch. 11 It is clear that the color of the red birds at least is 

 not changed secondarily through a change of sex, since birds of both sexes were 

 of this color. 



F'HYSICAL DEGENERACY AND RED- AND-WH1TE COLOR ASSOCIATED WITH LATE SEASON 

 AND WITH INBREEDING IN GRAY BRUNN POUTERS. 



A few gray Briinn pouters were bred for two or three years. The number of 

 pairs and the number of young are not large. The results, however, clearly sup- 

 port other data indicating, () that the first egg of the season and the autumn 

 eggs are "weak" germs; (&) that. white and red colors and physical degeneracy arc 

 hen- associated with the periods of "weak" germs; and (c) that in inbreds degen- 

 eracy and red and white colors readily appear. The data for (a) and (b) were ob- 

 tained from a mating in 1908-9, and are fully given in table 79. The female of this 

 series hatched 12 young in 1908. The colors of the first, eighth, ninth, tenth, 12 and 

 twelfth (Nov. 11) of the season showed weakness of coloration (red or white). 

 The eighth, ninth, and tenth (late autumn) show unusual red or white; the tenth 



EXPLANATION OF PLATE 17. 



A. .Juvenal pair (C 1 and C 2) of gray pouters from a brother-am l-*i,ster mating (pair 3 of table' SO). 



Photographed at 7 weeks. 



(' I (to the left) was of nearly normal color (sec table 80, pair 3)^. 



(' ,1 (to the right) is quite a departure; it is practical!!/ white-barred thri/ii<//i<iiil, i.e., every row of feathers on the 

 wing is white, broadly tipped with brown orange. The bird has varicating legs to sonic extent and is a weakling, 

 though not conspicuously so in other respects than the excess of white color and leg varication. It has a white band 

 in the tail and "frills" in the tertials. 



B. Juvenal pair (Xos. 8 and 9) of pouters from gray (white-barred) parents; 12 weeks old (see 



table 79): 



The great unlikencss of the two young is shown. The one (Xo. 9) was white, and was unable to fly. The pri- 

 maries were not well developed and were not closed, but hung at many angles. The- legs sprawled aparl, so that 

 walking was very awkward. The bird ate well, but had a very shaky behavior; (he head-movement was nol normal 

 but shaky, as in high-bred I'antails. The bird was a degenerate. The male (Si was a fine, sleek bird, well developed 

 and perfect in feather, but also a degenerate in color and in failure to lay eggs. When adult (he red-black wing-bars 

 (shown in the illustration for I lie j u venal > turned to white with black borders, but retained a tin^e of red. The latter 

 bird is higher in development than the former. 



EXI'LA NATION OK 1'l.ATK 18. 



A. Adult gray pouters (son and dam; see table 79) and one of their offspring (./, Aug. ">. 1909; 



see table 79) in Juvenal plumage. 



The sire and dam (to right and left) are similarly and normally colored. 



The young bird (,/) stands in the center. The photograph was taken at 7 weeks and shows I he rock-gray color 

 and presence of two black bars. 



B. Adult gray pouters (male No. 4 and female No. li of table 7!, and two of their color-modified 



offspring (El and E .' of August 9 and 11, 1909: see table SO). Photographed Oct. l(i, 

 190!); the young at 7 weeks old. 



The adult male stands to the left (front); the female stands behind I he male. 

 A' / is at the extreme right. The color of this bird is rock-gray with two black bars. 



K .' is at (lie center. This bird is red throughout ; there are no wing-bars, and the bases or proximal parts of the 

 fi-Mthers are whitened. 



11 I'nfortunately the relative irriylilx of these eggs is unknown; in many (or most?) domestic pigeons the usual 

 order (for wild species i, for both si/.e and prospective sex. is maintained quite loosely or not at all. EDITOR. 



'-The numbers in the table are tag numbers given to the birds. The second bird hatched was given no number; 

 therefore 'ninth" and "tenth" above 1 correspond to birds numbered (8) and (9). Kurroii. 



