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Show 558 MR. F. E. BEDDARD ON A NEW [Dec. 12, time, but in 1903 tlie mating a was repeated in the experiment y, in which the identical birds used in a were again mated together. In this experiment a uniform generation was obtained. A pair of birds bred in this F. 1 generation were mated together and the result is recorded in exp. c. The total results of the mating of Barb and Nun are:- (Exp. a, y) F. 1 : shell present 2 ; shell absent 10. (Exp. /?, ci) F. 2 : shell present 3 ; shell absent 11. I can also mention here that two birds which were crosses, in the F. 1 generation, between a Nun and a Fantail, kindly sent to me by Miss Thiselton-Dyer, showed no trace of " shell." These birds were not bred from. The experiments here recorded form part of a larger investigation into heredity in Pigeons still in progress, which has been subsidised by the Government Grant Committee of the Royal Society. I am indebted to Mr. J. Lewis Bonhote for raising and recording birds bred in Exp. 14, also to Mr. R. J. Elwell for raising birds in Exps. 9 and 12. I have also to thank Mr. Bateson, who has most kindly supervised all the experiments. 8. On a new Species of Worm of the Genus Pontodrilus from the Shores of the Red Sea. B y F rank E. B ed d ard , M .A., F.R.S.., Prosector to the Society. [Received October 5, 1905.] (Text-figures 78 & 79.) The specimens of Pontodrilus upon which the following description is based were kindly placed in my hands by Mr. Cyril Crossland, F.Z.S. They were collected by that gentleman ‘‘ in clean shell and coral sand on the shores of an islet in Khor Dongola, on the Soudan coast." Mr. Crossland further informed me "that the worms " live about the highest level at which the sand is kept wet by the sea. As there is practically no rainfall the water in which they live is undiluted by rain almost always. A species of Nereis and some Crustacea share this habitat." There is thus no doubt about the purely marine surroundings of this Pontodrilus, which so far agrees with the majority of the species of the genus. The general aspect of the worms was like that of the other species of Pontodrilus with which I am acquainted. The length of the largest and fully mature example was 102 mm., the size being thus about the average size of the species of this genus. |
