1905.] MR. J. LEWIS BONHOTE ON HYBRID DUCKS. 149 



Mr. Bonhote first dealt in a general way with the appearance 

 of the various specimens, pointing out how the three parent 

 hybrids between the Mallard, Spotbill, and Pintail tended to 

 divide themselves into two distinct forms — a light and a dark, 

 which differed chiefly in the amount of white. 



The light forms when bred together produced birds as light or 

 slightly lighter than themselves ; a tendency which was confirmed 

 in a still more marked manner in the third generation, so much 

 so, that in a full-plumaged drake the only sign of its parentage 

 was represented by the spotted bill of A . 2^<^ciiorhy7icha and the 

 upturned tail-coverts of the Mallard. 



It was fui'ther pointed out that, as in the case of the Mallard- 

 Spotbill hybrids*, so in the case of the Mallard-Spotbill- Pintail, 

 the drakes in their full plumage showed chiefly signs of the 

 Mallard and Pintail, whereas in the eclipse plumage the Spotbill 

 was largely predominant. 



Mr. Bonhote then briefly discussed some of the results obtained 

 by hybridisation, after laying stress on the antagonism between 

 Natural Selection and Variation, and how the one tended to 

 keep the species pure and fixed in spite of the innate tendency 

 of every individual to vary, and also pointing out how, in spite of 

 Katural Selection, marked variations were constantly making their 

 appearance among pure species — as, for instance, in the so-called 

 Pavo nigripennis, or in Athene chiaradice, a peculiar form of the 

 Little Owl (which was described from Italy a few years ago), or, 

 again, in the well-known Sabine's Snipe. 



Whatever might be the actual cause, there could be no denying 

 the fact that hybrids tended to show^ a considerable amount of 

 variation, exhibiting characteristics which might be very mis- 

 leading to those who did not know their parentage. 



As a rule, hybrids, while showing on most jDarts of their body 

 the characteristics of their parents, exhibited in addition other 

 markings. These last sometimes resembled the characters of 

 other species, but in certain cases showed affinity with no known 

 forms. Further, there was a gTeat tendency to become white, 

 and this last feature was ascribed to weakness, as it tended to 

 increase in each generation that was further removed from the 

 pure wild species. 



Instances were given where, in certain characters, individual 

 Mallard-Sj)ot bill- Pintail showed resemblances to Teal, Gadwall, 

 Wigeon, etc., and where Mallard-Spotbill-New Zealand crosses 

 showed resemblances to Teal and Pintail. 



Other specimens were also exhibited, showing patterns and 

 markings that resembled no known species. 



Mr. Bonhote did not believe these resemblances to be due 

 to reversion, but merely to variation ; pointing out that in all 

 probability the progenitors of the existing Anatidfe had a 

 potentiality of variation as great as or even greater than that of 

 their descendants of today, and that ovir present species showed 



* P. Z. S. 1902, vol. ii. p. 318. 



