339 
offspring of two animals clearly distinct may of themselves be per- 
fectly fertile, it is not proved that this fertility extends to a second 
generation. 
There is one other point which I must be allowed to mention 
before quitting the subject. It will be seen that the two birds ex- 
hibited differ remarkably in plumage, although of the same parentage, 
sex, and age; for they were born and killed within a day or two of 
each other. The larger specimen almost exactly resembles his 
father, but perhaps his colours are not so warm or brilliant. The 
smaller bird is of an appearance altogether distinct, and the almost 
uniform mottled grey of his breast and belly would make it perhaps 
difficult to guess his parentage. I can account for the divergence 
only in this way, that the Domestic Duck from which these birds 
are descended was of that almost whole-coloured variety which is 
not unfrequently seen in farm-yards, and that, while one of her 
grand-children shows nearly the typical plumage of the hybrid be 
tween the Wild Duck and the Pintail, the other takes after some 
progenitor of the variety I have mentioned. Whether this will serve 
to illustrate the peculiarity I have above mentioned, and also a curious 
fact alluded to by our Secretary in a late communication on some 
Hybrid Ducks bred in the Society’s Gardens, wherein it is stated 
that the produce of a cross between Tadorna vulpanser and Casarca 
cana present a character “ scarcely deducible from either,* ”’ I do 
not say. It is not, however, difficult to see what use may be made of 
this singular cireumstance by those who advocate the views of Mr. 
Darwin ; but into any consideration of the question I forbear to enter, 
contenting myself merely by noticing the fact. 
6. Remarks on THE Anas (ANSER) ERYTHROPUS OF LINN&EUs. 
By Autrrep Newron, M.A., F.Z.S. 
The determination of the species established by Linnzus has 
always been held by naturalists a matter of so great importance, 
that I have no scruple in occupying a portion of your time this 
evening with a few remarks respecting the bird which, in the 12th 
edition of his ‘Systema Nature’ is designated by the name of 
“* Anas erythropus ;”’ especially also as one of his editors (the late 
learned Professor Retzius), though noticing the “mira circa hance 
avem confusio,”’ has, in my opinion, failed to give a satisfactory 
solution of the difficulty. It will be, I think, universally admitted 
that the names employed by Linnzus, when, as in the present in- 
stance, they are drawn from any physical character, are remarkably 
apposite. This consideration of itself should have served as a warn- 
ing to ornithologists against their imagining, as many have done, 
that he could possibly mean to apply the name ‘“‘ erythropus” to a 
species like the Bernicle Goose, with which he was sufficiently 
familiar, and to which it was in no degree suitable. 
* Proc. Zool. Soe. 1859, p. 442, Aves, Pl, CLVIII. 
