‘“RULIPSE” PLUMAGE IN THE MALLARD. Al 
to say that half the area on the breast and abdomen, which 
is normally vermiculated, exhibits the eclipse plumage, while 
the rest is in male or winter plumage. This bird (No. 75) was 
castratedin May. In the middle of July its general appearance, 
whilst standing, was quite male, for the only obvious sign of the 
oncoming of the eclipse was a slight loss of the gloss on the 
vertex of the head and a browning of the cheeks; the curl 
feathers in the tail were still unshed—. e¢., the appearance of 
the eclipse was delayed, as usual, after castration. But on 
lifting up the bird, it was seen: that the abdomen and breast, 
where they had been plucked for castration in May, were covered 
with a thick growth of buff and black eclipse feathers. Although 
this is the most marked example of the growth of eclipse feathers 
in plucked areas of castrated birds otherwise in winter plumage, 
we have seen the same thing in a less degree in other cases. 
Text-figure 6. 
A Mallard (75) castrated in May. 
The abdomen and lowest part of the breast (plucked under ether anesthesia for 
castration) have become (middle of July) covered with a growth of buff and 
black eclipse feathers, the plumage being otherwise of the winter kind, 7. e. the 
appearance of the eclipse elsewhere has been delayed. 
The ducks distinguished as Nos. 18, 48, and 69 were killed 
during late summer or early autumn, 7. ¢. at a time when the 
testes are normally in an inactive condition. We unfortunately 
omitted to examine the histological condition of the “ grafts” in 
No. 18, killed July 30th, 1908; but in the case of No. 48, killed 
