“CRCLIPSE” PLUMAGE IN THE MALLARD. 39 
a carraway seed, and two others about the size of a grain of 
maize and of a hemp seed respectively. 
(No. 19.) Bird in full eclipse; castrated July 12th, 1906. 
The testes removed were of medium size, 15 mm. in longer 
diameter; the weight of each was about 3700 mg. The tubuli 
were fairly large, and distended with cells, without lumen. Here 
and there the spermatid sheaf arrangement was indicated. There 
were, however, no properly formed and stained spermatozoa. 
September 11th, 1906.—Bird in almost full male plumage, 
except that the stippling on most of the vermiculated feathers 
has not attained its full darkness, and that the majority of these 
feathers are tipped with white. 
January 24th, 1907.—Bird in full male plumage; there are 
two curl feathers in the tail. 
April 4th, 1907.—Bird in full male plumage. 
July 27th, 1907.—Bird in almost full eclipse, though there is 
a slight gloss on vertex. ‘The grey upper portion of the breast 
is in eclipse, which must, however, be considered to be passing 
off, since there are many winter feathers coming through the 
down. The abdomen and the hinder part of the breast, eclipse. 
The wing-feathers have been moulted, but the new primaries and 
secondaries are not yet fully grown. There are no curl feathers 
in the tail. 
The bird was killed on July 30th, 1907. On the left side 
there was a nodule the size of a small haricot, loosely connected 
with the great veins below the normal site of the testis. A group 
of grafts. together as large asa filbert, was loosely attached to the 
back of the liver. 
(No. 13.) Bird in full eclipse; castrated July 8th, 1907. The 
testes removed were quite small, scarcely 10 mm. long by 5 mm. 
broad. The tubuli, of comparatively small size, were furnished 
with a well-differentiated lumen ; cells two or three deep: no 
spermatozoa. 
September 17th, 1907.—The bird still retains much of the 
eclipse plumage; there are some glossy feathers on the vertex 
and round the eye, but the rest of the head and neck are in 
definite eclipse, and the neck shows only the faintest remains 
of a white ring. The breast and the abdomen are in eclipse, 
though in both positions a few vermiculated feathers are coming 
through. The area which was plucked for the castration is 
slightly darker than elsewhere. On the flank many of the brown 
eclipse feathers are becoming vermiculated, and new vermiculated 
feathers are, in addition, appearing. ‘There are no curl feathers 
in the tail; the moult of primaries and secondaries in the wings 
has been much delayed, as the new feathers have not yet attained 
their full size, and their shafts are still vascular. 
November 18th, 1907.—The head is glossy, but many feathers 
on the cheeks are still partially brown; the white ring on the 
