1872.] LAMELLIROSTRES OF THE ARGENTINE REPUBLIC. 369 



This peculiar Duck is also found on both sides of the Cordilleras, 

 and may be seen occasionally in the vicinity of Bueuos Ayres, where 

 it has been sometimes killed by my hunter on the Laguna Matanza 

 at the south of the town. As the description given in Gay's work 

 is very short and only applicable to the summer dress, I think it 

 desirable to give a full description of this bird. 



The old male in the summer dress is of a dark reddish-brown 

 colour on the back, and somewhat paler, mixed with grey, on the 

 underside. The head and neck are black, or dark blackish grey, 

 mixed in the younger plumage with reddish margins to the feathers. 

 The wings are dark blackish brown with reddish spots ; and the tail 

 is clear yellowish grey ; the bill is blue-grey ; and the legs are black, 

 the iris dark red. 



The bill, somewhat shorter than the skull, is very high at the base, 

 and the plumes on the front are somewhat produced ; the flat apical 

 half is nearly of the same breadth, and the hook on the tip very 

 small. The small nostrils are placed in the middle, where the 

 flat apical half begins. The much narrower under mandible is 

 whitish, the upper mandible bluish grey, the hook reddish brown. 



The plumage is of a silky appearance, very soft and very compact ; 

 all the feathers are broad and rounded, and those on the back very 

 large. The wings are short, and do not reach the tail ; and the first 

 of the pointed remiges is the longest. The most peculiar orgau is 

 the tail, which consists of eighteen small very rigid feathers, succes- 

 sively longer from the outer to the middle, the first on each side 

 being shorter than the half of the middle. This strong rigid tail is 

 therefore cuneated, and passes directly out of the plumage without 

 any tail-coverts, as is the case with many other Ducks, the plumage 

 being transversly cut off at the commencement of the tail on the 

 upper and under parts. The feet are large ; and the outer toe is twice 

 as long as the tarsus, which is much compressed ; the hinder toe is 

 small and furnished with a small membrane; the whole foot is black. 



My specimens measure 14 inches long; the bill 1^ inch, the 

 closed wings (which have a small tubercle on the . hand-joint) 5 

 inches, the tail 3 inches, the tarsus 1| inch, and the outer pha- 

 lanx 2\ inches. 



The young male and the female are of entirely different colours, 

 but have the same style of plumage. The whole of the upperside 

 of the body is a blackish brown, each feather having a thin yellowish 

 grey or whitish margin, which gives to the back an undulating ap- 

 pearance. The underside is whitish grey, or yellowish grey, with 

 faint blackish-grey undulations, as every feather is dark grey, but 

 with a large white or yellowish edging, which covers the whole of the 

 grey part so that only here and there the grey ground is to be seen. 



The wings and tail are blackish grey, the latter being somewhat 

 yellowish. A small whitish or yellowish stripe commences at the 

 sides of the bill, and passes under the eye to the neck, terminating 

 over the ear. This white stripe is lighter in the female ; the whole 

 of the throat and sides of the neck are of the same colour, so that 



Proc. Zool. Soc— 1872, No. XXIV. 



