36 DR. C. G. SELIGMANN AND MR. S. G. SHATTOCK ON THE 
is one glossy curl feather in thé tail, probably new; two other 
feathers are beginning to ridge. Tail-coverts glossy. 
Text-figure 5. 
Mallard (2), photographed September 11th, 1907. 
The bird was castrated in December 1906. The advent of the eclipse in the summer 
of 1907 was delayed. The photograph shows that the passage from the 
eclipse to the winter plumage is also delayed; the plumage is still pre- 
dominantly eclipse; the vertex was only slightly glossy; the white ring has 
not reappeared on the neck; there was but one curl feather in the tail. 
January 24th, 1908.—Bird completely male; four good curl 
feathers in the tail. On the flanks there is an occasional feather 
of a dusky brown colour with obscure vermiculations. 
This bird was killed on February 19th, 1908, when a spheroidal 
graft, 6 mm. in diameter, was found in the abdomen. The tubuli 
of the graft were of full size, and active spermatogenesis was in 
progress. 
(No. 48.) Bird in full winter plumage; castrated March 6th, 
1907. 
May 14th, 1907.—Bird in full plumage, with three curl feathers 
in the tail. The only premonition of the eclipse is a slight 
browning of some of the interscapular feathers and those upon 
the lower part of the breast. 
July 11th, 1907.—The plumage has undergone but little 
