558 ■ MR. r. E. BEDDARD ON A NEW [Dec. 12, 



time, but in 1903 the 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 

 I'esult is recorded in exp. c. 



The total results of the mating of Barb and Nun are : — 



(Exp. a, 7) 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 wei-e crosses, in 

 the F. 1 generation, between a Nun and a Fantail, kindly sent 

 to me by Mi.ss Thiselton-Dyer, showed no trace of " shell." These 

 birds were not bred from. 



The experiments here recorded form part of a larger investi- 

 gation 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 bi-ed in Exp. 14, also to Mr. R. J. Elwell for luising 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 Genns Pontodrilus horn 

 the Shores of the Red Sea. By Frank E. Beddard^ 

 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 

 Orossland, 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. Orossland 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 inature example was 102 mm., 

 tlie size being thus about the average size of the species of this 

 aenus. 



