1899.] F. Finn — Notes on the Floceidie. 253 



the two species in captivity, wliicli might easily be done. Atth(isame 

 time, in confirmation of the interbreeding theory, it may be mentioned 

 that Dr. Butler in the work above quoted (p. 220) cites Dr. Karl Rusa to 

 the eifect that the African Aidemosyne cantans and its very near ally the 

 Indian A. malabarica, which do not meet in a wild state, interbreed 

 indiscriminately in captivity. In view of cases like these, and of the fact 

 that extreme forms of intergrading species, such as Corvus corone and 

 C. cornix^ and Coracias indica and 0. affinis are positively known to pair 

 lip together, I cannot accept the theory that such intermediate speci- 

 mens as occur midway in the range of intergrading forms represent the 

 parent species in its as yet undifferentiated form, as has been advanced 

 by some naturalists. For the progenitor of two given species need not 

 have necessarily been an absolutely intermediate type, though the 

 hybrid may be so, as has been proved by experimental breeding. For 

 instance, we may presume that the ancestor of two species the males 

 of which exhibit decorative colours, would have resembled the duller 

 females and young of the existing forms ; e.g., the primitive ancestor 

 of the common Bullfinch (FyrrhuJa europ&sa) no doubt resembled 

 P. miirina of the Azores, and that of the Linnet (Linoia cannahina) 

 the duller coloured Twite {Linota tiiontium). Yet when these two Finches 

 are crossed in captivity, the " mule " has a pink breast, a piece of de- 

 corative coloration which was almost certainly absent in the common 

 progenitors of the Bullfinch and Linnet genera. 



Lastly there is strong reason to suspect that species arise suddenly 

 as far as colour- variations are concerned. The Red-headed form of the 

 beautiful Gfouldian finch {Poephila Tiiirdbilis), is an example, and is es- 

 pecially interesting as showing how such sports may tend to increase, 

 as it has been found by Dr. Butler to be more attractive to the hen than 

 the less brilliant black-headed variety. {Op. cit. p. 176). 



3. A SUGGESTION FOE A MORE NATURAL CLASSIFICATION OF THE 

 PLOCEIDiB. 



Considering that this group of Passerine birds has been studied far 

 more thoroughly than any other, being well known in captivity (in 

 which state many species breed) it is rather remarkable that ornitholo- 

 gists have not availed themselves to a greater extent of the exceptional 

 opportunities thereby afforded them of arriving at a natural classification 

 of the group. As a matter of fact, any one who has studied these birds 

 in life will see that the greater or less development of the first primary 

 can hardly be deemed a character of importance as contrasted with the 

 marked difference of colouration, general size, and habits, which separate 

 the true Weavers, with their near allies the Whydahs, on one hand, 



