Letters, Extracts, and Notes. 391 



Count Salvadori does not consider the characters of 

 Melanonyx But. of generic value, whereas I do. 



This is too difficult a question for me to discuss at length 

 here, and I shall only say a few words to explain the reason 

 why I consider the genus well grounded. The absence in 

 Melanonyx of the black markings on the breast and belly, as 

 well as their presence in the species of the genus Anser 

 (sensu stricto), shew us, most decidedly, that the birds of these 

 genera have descended from two distinct and ancient ancestral 

 types — types as distinct from one another as the ancestral 

 type of Eulabeia was from them. In fact, the black bars 

 on head of Eulabeia indica ought to be regarded as of great 

 antiquity, and it is impossible to suppose for a moment that 

 they have been acquired in comparatively recent times. 

 For this reason these bars are proof, for me at least, of 

 absolute generic rank, and are of the same importance as is 

 the presence or the absence of the black markings on the 

 under parts of Anser and Melanonyx. Why this is so I 

 hope soon to be able to shew in a work that I am now 

 writing, in which I shall treat of the differences between 

 generic and specific characters. These differences are now 

 often confounded by systematic zoologists, though I deny any 

 specific importance to, let us say, the presence or absence of a 

 white collar in the Pheasants &c. 



We know that in the Catalogue of the Chenomorphae 

 Count Salvadori does not accord generic rank even to 

 the genus Eulabeia, but that he does so to Chen and 

 Philacte. The author, however, in giving the characteristics 

 of Chen, omits the only one of absolute generic import- 

 ance, as I consider it, viz. the black bands along the 

 tomia, by which Chen is most decidedly to be separated 

 from all the other genera of the subfamily Anserince. 

 This character does not admit the keeping in this genus 

 of Chen rossi, which must be regarded as the type of 

 Exanthemops. 



At all events, if Eulabeia is not to be separated from Anser, 

 there is no plausible reason for maintaining Chen or Philacte ! 

 But such a classification would almost bring us back to 



