GOLDEN EYES, OR GARROTS—GILPIN. 
398 
a transient mark of the young, and that the adults of both 
species have dark bills : that the young should have gaudier bills 
than the adults, or the female than the male, is almost unknown 
in natural science. Here then we have two species, in the male 
easily distinguished by colour, but in the female by colour impos¬ 
sible, and our only guide is that the Rocky Mountain bird, 
though larger, has a shorter and higher bill, and in consequence 
of this height a difference in the shape of the forehead, where the 
feathers meet the culmen, tolerably well enough shown in the 
male adults, but more obscurely in th$ female and young—all be¬ 
ing in the recent state, and in the dried or mounted specimens 
scarcely discernible. Dr. Coues, the last American writer upon 
the subject, says: “ Female doubtfully distinguished from that 
of clangula (common golden eye) with certainty, unless by the 
dark bar in wing,” and again, “ doubtfully distinct from the last, 
-fooea which I am not prepared to unite it,” Coues, 290 Key, N. 
A. birds. In searching further for some typical mark of distinc¬ 
tion, I was led to the anatomy of the birds, but whilst finding 
little or nothing in the parts of reproduction, the ovaries and testes, 
I unexpectedly found in the male birds so great a difference in 
the shape of the windpipes as at once to mark a different species. 
This difference is much more easily seen than described, as is 
readily shown in the plate. In the male common golden eye, 
the wind-pipe soon after leaving the throat and before it enters 
the breast, has a very sudden enlargement, almost as it were a 
broad hoop thrown obliquely around its stem, on the inside this 
leaves large circular pouches on the posterior surface before the 
restriction of the pipe rakes place again. In the Rocky Moun¬ 
tain species, the wind-pipe simply and gradually enlarges itself, 
becoming restricted again before it enters the breast. In one the 
enlargement is suddenly from 2-8 of an inch to an inch and an 
1-8, while in the other from 2-8 to 5-8 inch, and that with no 
protuberances. In the males alone of both species there is, after 
the wind-pipe has entered the breast, that very complicated sub- 
quadrangular knob, from which the bifurcation of the pipe pro¬ 
ceeds. This form is common in a modified degree to other 
species. According to our present ideas of species, this great 
