io8 



1884 and 1889, viz. that in salmon in the Rhine, when prevented, 

 through shoal water or shifting gravel, from laying their eggs, 

 the spawn was retained in the body, and embedded in fat, so 

 that the female salmon in question became absolutely sterile. 



E. B. PouLTON said that Mr. Fryer must be congratulated 

 on his success in the difficult task of breeding P. polytes through 

 a series of generations, and on the interesting results he had 

 obtained thereby. The speaker was unable to accept the con- 

 clusion that the proportions of the different female forms of the 

 species were determined by the Mendelian relationship unañected 

 by selection. Geographical changes in the mimetic female forms 

 of P. dardanus followed the presence or absence of various 

 Danaine models, as he had described and illustrated in his intro- 

 ductory address. No hypothesis except selection had been sug- 

 gested to account for the phenomena exhibited by P. dardanus, 

 and he should find it very hard to believe that proportions of the 

 females of polytes were determined by an entirely different principle. 

 He had, in fact, been told at that very meeting, by Dr. Adalbert 

 Seitz,^ that the excessive rarit}^ (very rarely amounting to 

 entire absence), of the chief Papilio model at Hongkong was 

 accompanied by an equal rarity of the corresponding mimetic 

 female. Furthermore Mr. W. Rothschild and Dr. Karl 

 Jordan had shown that geographical change in the amount of 

 white in the hindwing of this model was also found in the 

 pattern of the mimicking female. 



C. Annandale pointed out that Prof. Poulton's instances of 

 work done on encouragement from the Hope Department actually 

 bore out his view that it was important that zoological work 

 should be done in the tropics. He realised the great help given 

 by the Oxford Museum to workers in the tropics, and maintained 

 that there was a strong feeling in some museums that zoologists 

 in the tropics should act merely as collectors. 



T. A. Chapman said that, in reference to Dr. x\nnandale's 

 remarks on fertility in captivity, an observation on Acronyda 

 alni some twenty years ago showed that bred specimens, not 

 related, would pair freely, but no eggs were laid, but in all instances 

 — some five or six — in which a wild male was obtainable, pairing 



1 Dr. S EiTz's observations are now recorded in full in Proc. Eut. Sec. 

 Lond., May 7th, 1913. 



