552 ME. R. STAPLES-BROWNE ON [DeC. 12, 



ordinary blue colour found in Volumha livia. The feathers on 

 the back of the head were perfectly smooth (c/. ISTun Pigeon). 



It was bred by Mr. Doggett, of Cambridge, in 1896, from a pair 

 of bii-ds with peifectly normal feet. The parents produced several 

 offspring showing webbing in varying degrees. Three of these 

 birds were exhibited by Mr. Bateson at the Zoological Society, and 

 are described in the 'Proceedings' for Dec. 15th, 1896, p. 989. 

 (The bird used is No. 3 in that description.) 



It was also desci-ibed and the right foot figured by Mr. Tegetmeier 

 in ' The Field' of Sept. 12th, 1896. 



It appears that some of these birds were bred together and 

 produced, among others, a bird with completely webbed feet, the 

 web being sufficiently loose to allow the normal spread of the foot 

 between every digit. This bird was exhibited by Mr. E. S. 

 Montagu at a meeting of the British Ornithologists' Chib on 

 Jan. 22nd, 1902. It is described in the report of the meeting 

 (Bull. B. O. C. xii. p. 41), and again in 'The Field' of Feb. 1st, 

 1902 (vol. xcix. p. 177). 



" I^un " Pigeon $ used in Experiments. 



The Nun is an old established strain of Pigeons, originally a 

 variety of Tumbler. The feet are normal and free from feathering. 

 It exhibits a tuft of reversed feathers standing np at the back of 

 the head forming the "shell." It is slightly larger than the peak 

 found in the Tui'bit and some similai' vai'ieties. 



Crosses hetiveen the Web-footed Pigeon and the Nun Pigeon. 



The experiments were begun in 1902. The original cross Avas 

 made between one pair of birds only, viz., those described above. 

 The subsequent experiments consisted of breeding from the birds 

 produced by the first cross. 



The results of the experiments, so far as they concern the two 

 principal characters of w^eb-foot and " shell," are given in Table I. 



The table is arranged in a similar manner to that used by 

 Bateson and Punnett in the description of their experiments with 

 Poultry in the second report to the Evolution Committee of the 

 Royal Society. The ordinary Mendelian terms are used : — 



D and E. being the original dominants and recessives ; 

 DR is the first hybrid generation or F. 1 ; 



WW 



■ the heterozygote dominant in F. 2 ; 



the homozygote dominant in F. 2 ; and 



— the extracted I'ecessive. 



2 



The same terms over 3 apply to similar forms in F. 3. 

 The asterisk shows that the bird is bred from a DR x R mating, 

 and not from a DR x DR. 



