ON THE NATURE AND BASIS OF HEREDITY. 185 



In a pair of young pouters from gray (white-barred Briinn) pouters, one (8) is 

 gray with dark bars, and in form is apparently very well developed;"' the other (9) 

 is white, with poorly developed wings, the primaries being imperfectly developed.'^ 

 This bird has the "shakes"; that is, it trembles all over and can not control the 

 movements of the head (I have had two such white birds from a dealer, and they 

 are evident!}^ of the same nature). This bird was hatched October 11, 1908, and 

 at the age of 5 to G weeks, though of good appetite, was quite unable to fly. 

 This white pouter died Januarj' 27, 1909, and turned out to be a female, as was its 

 nest-mate, both hatched in October 1908. 



In another case a pair of birds consisting of a male orientalis x risoria hybrid 

 (8) and a female St. alba hatched both eggs of a clutch on June 5, 1908; and again 

 both eggs of another clutch on July 7. They laid again (third time) July 22 and 24, 

 when the young from the second clutch were only about 2 weeks old and not yet 

 out of the nest. This set of eggs, })roduced so early after the preceding eggs, failed 

 to develop. Either this was due to the presence of young in the nest (the latter 

 would prevent steady sitting) or to weakening of the germs (late in season) and to 

 the strength of the old birds being reduced by the care of vigorous young. 



Short abnormal legs. — In several crosses between common pigeons (C. livia 

 domestica) and T. orientalis of Japan, I have had young hatched with legs abnor- 

 mally short, so that in course of a few days, as the body rapidly grew, the legs came 

 more and more to point more or less directly backward, and to be of no use in 

 enabling the bird to reach up for its food. 



So far as memory and some records serve, this condition did not appear in any of 

 the first offspring raised in the better part of the season — ^April to June — but in the 

 later offspring of July and August. This deformity may, then, be ascribed to failing 

 or diminished germ-energy. 



This view is confirmed again this season (1909) in a cross between a homer and a 

 hybrid between T. turtur and T. orientalis {TO S). The products of this cross (up to 

 July 22) are as follows: 



First set of eggs, April 12 to 11, miriii.-il drvclopment. 

 Second set of eggs, April 22 tc 2 1. linnii:,! .lovelopment. 

 Third set of eggs. May 1 ti, :j, iioniKil .1. •^ , Icpment. 



Fourth set of eggs. May 16 to is. hkiI development. 



Fifth set of eggs, May 2S to 30, normal development. 



Sixth set of eggs, July 1 to 3, first, short legs; second, legs normal. 



Note that I have worked these birds abnormally rapidly, and probably that, 

 added to the usual strain, has been sufficient to weaken reproductive power. In the 

 earlier part of season transference of eggs is followed by immediate renewal of 

 the nesting cycle. In the later part of season the birds lose a week or more before 

 renewing their efforts. 



Distorted development, wry neck, dolicocephalisni. — In 1906 I mated an imported 

 male Japanese turtle with a female hybrid (SO 2) obtained in 1904 from a cross of 

 St. risoria and T. orientalis. The result was one secondary hybrid {c^O-SO 2-B) 

 which was able to live and mature. This bird has thus far proved infertile. He 



"A neat bird but a degenerate, as shown by color and also by her early failures to produce eggs. 



" The feathers of this bird were slow and irregular in growth; it was never able to fly, though it lived Sj months. 

 It was kept in the house and well cared for; no cause of death but weakness. The legs spr.awled, so that walking was 

 awkward and difficult; it was shaky like a fantail, and the primaries hung loosely apart. 



