100 INHERITANCE, FERTILITY, 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 "Aveaker germs," and 

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

 eggs of the pigeon's clutch." 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. 



PHYSICAL DEGENERACY' AND RED- AND-WHITE 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- 

 l)ort other data indicating, (a) that the first egg of the season and the autumn 

 eggs are "weak" germs; (6) that white and red colors and physical degeneracy are 

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

 eracy and red and white colors readily appear. The data for (a) and (6) 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,*- 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 brothcr-aiul-sister mating (pair 3 of table 80). 



Photographed at 7 weeks. 



C 1 (to tho loft) was of ncariy normal color isro tahir SO, pair :i). 



C 2 do il"' nil] A I i-^ i|uih' a dr|iailuir; ;/ / . i^nriirnih/ irliiti -In, rr, ,1 ilirniniliiiiil , i.e., every row of feathers on the 

 wing is wliiir, l.r.iM,ll\- iippid wiih l.iuHM niaimr. The lai.l ha- vaM.'aiinii Ici^s lo some extent and is a vveakling, 

 though not coiispK iioii-ly so iii olhcr ivspn l- I lian I lir cxcr-s of whllr coll II- and Icf; vai'ication. It has a white band 

 in the tail and •'frills" in tlu; lertiuls. 



B. Juvenal pair (No.s. 8 and 9) of pouters from gray (white-barred) parents; 12 weeks old (see 



table 79). 

 The great unlikene.ss of the two young is shown. The one (No. 9) was white, aid »a- nnalilc to fly. The pri- 

 maries were not well developed and were not closed, but hung at many angles. The Icn. vpiMulcil apart, so that 

 walking was vcrv awkward. The bird ate well, but had a very shaky behavior; the licad-iiio\aaiiciit was not normal 

 I, 111 -h:>l;\ , a- 01 hi-hd.ivil fantails. The bird was a dc^caicralc. The mate (8) was a fine, sleek bird, well developed 

 :ina pel h ri ill leii hi I . liut also a degenerate in color ami in failure Pi la\' e!j;Ks. When adult the red-black wing-bars 

 i.|i,,\Mi III I he ilhi-iiaiioii for thojuvenal) turned to white wil li l)lai-k lioideis, but retained a tinge of red. The latter 

 liiid is higher in development than the former. 



Explanation of Plate 18. 



A. Adult gi-.'iy piiiilci-s (son and dam; see table 79) and one of their offspring {J, Aug. 5, 1909; 



sro t:ililc T'.t) in Juvenal plumage, e 

 The sue ami il iiii lo right and left) arc similarly and normally colored. 



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

 and presence of two black bars. 



B. Adult gray pouters (male No. 4 and female No. 6 of talile 79), and two of tlicir edlor-niddified 



offspring {E 1 and E 2 oi August 9 and 11, 1909; s,r tabh- SO). Plnitographed Oel. Ki, 

 1909; the young at 7 weeks old. 



The adult male stands lo the left (front); the female stands behind ihe ni.ile. 



£; / is at the cxireine right. The color of this bird is rock-gray willi two bl.ick bars. 



E ^ is at Ihe c. nil r. This liird is red throughout; there are no wing-liais, and the bases or proximal parts of (he 

 feathers are whip ih d 



I'Unforiiiii iP l\ Ihe refiiue M ',//,/s ,,f these eggs is unknown; in many o,r mosi ') domestic pigeons the usual 

 order (for u iM -pem - , ha Imih -i,.e :iii.l prospective sex, is maintained quile f .n-el\ m n.it at all. — Editor. 



"The imiiilieis III Ihe lalile are lag numbers given to the birds. The -siM'ond laid liairhed was given no number; 

 therefore "ninth" and ■'Iciilir above correspond to birds numbered (S) and I'.ti. - Ivni icnt. 



