Anatine Genus Nyroca and Its Nearest Allies. 109 
Ilyonetta HEINE. Nomencl. Mus. Hein. Ornith., 1890, p. 347 (nom. emend. 
pro Nyroca Fleming, 1822; type, therefore, Anas nyroca Giildenstiidt). 
Diagnosis —Similar to Fuligula, but length of wing less than 5 times 
the length of exposed cuimen ; head without a long occipital crest. 
Description—Wing 42/5-44/5 times the length of exposed culmen ; bill 
relatively somewhat flattened terminally, its width near end 1-1 2/10 times 
its width at base, its tip rounded, its width at posterior end of nail 1 9/10- 
23/10 times the length of nail: tip of maxilla much hooked; nail of bill 
broad and triangular; height of bill at extreme base 9/10-1 2/10 times its 
greatest width; base of culmen not deeply concave; exposed culmen 1 4/5- 
21/5 times the height of bill at extreme base, and 19/10-21/5 times the 
greatest width of bill; exposed culmen decidedly less than the length of 
inner toe with claw: anterior outline of feathering at the base of culmen 
triangular and acutely pointed: feathering on sides of maxilla not reaching 
forward as far as that at the base of culmen: a short occipital crest or none. 
Type.—Anas nyroca Giildenstiidt. 
Remarks.—The species included under this heading seem at first sight to 
be a heterogeneous assemblage, but, as in the case of Fuli«x, the examination 
and comparison of all the species involved and the proper consideration of 
individual yariation show that no further generic division is possible with- 
out virtually making a genus of each species on characters either trivial 
or not wholly constant. It is quite true that Vyroca americana differs in 
structure considerably from Nyroca nyroca, the length of the wing in the 
former being more than 41/2 times the exposed culmen; the bill less wid- 
ened at tip, its width at posterior end of nail less in propertion to the length 
of the nail, its height at extreme base decidedly more than its greatest 
width; and the length of the exposed culmen decidedly more than 2 times 
the greatest width of bill; but all these differences are more or less unsat- 
isfactory, as they either by individual variation or through the characters 
of other species here referred to Nyroca grade insensibly into each other. 
The same situation exists in the other species. Two forms, Vyroca nationi 
and Nyroca innotata, haye not been examined in the present connection, but 
the relationship, of at least the latter, in so far as determinable, seems to 
be doubtless with the present group. 
No complication exists in the generic synonymy of this group, for the 
name Nyroca Fleming* has for its type by tautonymy Anas nyroca Giilden- 
stiidt. The /lyonetta of Heine? is, of course, merely a substitute name for 
Nyroca Fleming, for reasons of purism. 
The species belonging to this genus are as follows: 
Nyroca erythrophthalma (Wied) 
Nyroca brunnea Eyton 
Nyroca nationi (Sclater and Salvin) 
Nyroca americana (Eyton) 
Nyroca nyroca (Gildenstiidt) 
Nyroca innotata Salvadori 
Nyroca australis Eyton 
Nyroca baeri (Radde). 
‘Philos. Zool., II, 1822, p. 260. 
*Nomencl. Mus. Hein. Ornith., 1890, p. 347. 
