On the Hybridising of Ducks. 263 



been unable to cross the dark Pintail trigens ? And, further, 

 I have this year bred a pure white New Zealand trigen which 

 was always the strongest and largest of the brood and is now 

 the sole survivor, and has since proved perfectly fertile. 

 I have merely noted these apparent contradictions here to 

 show that I am not unmindful of them, and in fact an 

 explanation is not impossible ; but the matter is not as yet fully 

 elucidated, and consequently the explanation is best deferred. 

 This completes my notes so far as they have gone, and if 

 it may be justly said that they are somewhat incomplete, 

 nevertheless it may with equal fairness be maintained that 

 they are suggestive enough to warrant the hope that the time 

 and money spent has not been in vain, and I would hope that 

 others more favourably placed than myself may take up and 

 try to elucidate some of these problems that form the bedrock 

 of modern zoological science. 



Summary. 



This paper being from its nature somewhat lengthy and 

 involved, a short summary may not be out of place. The 

 various crosses that have been bred are shown in a table at 

 the beginning, and the method of indicating the exact 

 parentage of any particular cross is fully explained on p. 237. 

 As we deal with crosses of more than two species it was felt 

 that a new term to denote these would have to be invented, 

 and with the help of Professor Newton and Professor Skeat, 

 the terms di-, tri-, tetra-, penta-, etc., with the suffix -gen, 

 have been adopted. 



The first part of the paper deals with the actual crosses 

 that have been obtained showing exactly how they have been 

 produced and accompanied by careful descriptions. All 

 deductions from the experiments have been kept for the latter 

 half, and the matter treated under five general headings, viz. : — 

 (1) Fertility, in which it is shown that most of the crosses 



under review are perfectly fertile. 

 (2) Sex. — Where it is pointed out that at birth the 

 sexes are approximately equal, but that during 

 infancy there is a greater mortality among the hens, 

 which gives rise to the opinion that most hybrids 

 are Drakes. 



