| OCR Text |
Show 552 MR. R. STAPLES-BROWSE ON [Dec. 12, ordinary blue colour found in Colaviha livid. The feathers on the back of the head were perfectly smooth (cf Nun Pigeon). It was bred by Mr. Doggett, of Cambridge, in 1896, from a pair of birds with perfectly 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 described and the right foot figured by Mr. Tegetmeier in £ The Field' of Sept. 1 2 th, 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' Club 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). " Nun " 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 Tip at the back of the head forming the " shell." It is slightly larger than the peak found in the Turbit and some similar varieties. Crosses between the Web-footed Pigeon and the Nun Pigeon. The experiments were begun in 1902. The original cross was 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 web-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 R being the original dominants and recessives; DR is the first hybrid generation or F. 1 ; -D-R the heterozygote dominant in F. 2 ; the homozygote dominant in F. 2 ; and 2 R.- the extracted recessive. 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. |
