112 Proceedings of Indiana Academy of Science. 
This genus in some.respects resembles Aristonetta, as for instance in the 
much concave base of culmen. in which character it differs from all the 
other groups here considered. It is, however, well differentiated from Avris- 
tonetta, as may be seen from the diagnosis under that genus. 
The generic name Aythya Boie' is the earliest name applicable to this 
group, but it is preoceupied by Acthya Dumont. which is a synonym of 
Aethia, the earliest name for the genus of Alcidae formerly known as Simo- 
rhynchus. The Aithya of Boie® is. of course, merely an emendaticn of Aythya 
Boie, and is also preoccupied by Aecthya Dumont. Likewise, Fuligula 
Swainson,’ the type of which by monotypy is Anas ferina Linnaeus, is pre- 
occupied by Fuligula Stephens.” The name Aithyia Gloger,® proposed as an 
emendation for Aythya Boie, is. however, by virtue of its additional syllable, 
a different word, therefore tenable under the present rules of nomenclature, 
and should be brought into use for this genus as its earliest valid designa- 
tion. 
The only species referable to Aithyia is Aithyia ferina (Linnaeus). 
Aristonetta BAIRD. 
Aythyia BONAPARTE, Compt. Rend, VAcad. Sci., XXXVIII No. 14, 
April 10, 1854, p. 664 (type by monotypy, Anas valisineria Wilson) (nee 
Aithyia Gloger). 
Aristonetta BAIRD, Rep. and Explor. Sury. R. R. Pac., TX, 1858, p. 793 
(in text) (type by original designation and monotypy. Anas valisineria 
Wilson). 
Anthya LE MOINE, Ornith. Canada, pt. 1. 1860, p. 90 (type, Anas va- 
lisineria Wilson). 
Diagnosis.—Similar to Aithyia, but length of exposed culmen about equal 
to length of inner toe with claw, more than twice the height of bill at ex- 
treme base, and about 3 times the greatest width of bill: length of wing less 
than 4 times the length of exposed culmen; bill rounded at tip, and not 
wider near end than at base; tip of maxilla little or not at all hooked, 
Description — Wing 33/4-34/5 times the length of the exposed culmen ; 
bill much flattened terminally, its width near end not more than its width 
at base, usually less; tip of bill rounded; width of bill at posterior end of 
nail 21/5 tinies the length of nail; tip of maxilla little or not at all hooked ; 
nail of bill narrow and straplike; height of bill at extreme base 1 1/4— 
times the greatest width of bill: base of culmen deeply concave; length of 
exposed culmea 22/5 times the height of bill at extreme base, about 3 
times the greatest width of bill. and equal to the length of inner tee with 
claw ; anterior outline of feathering at base of culmen triangular and acutely 
pointed ; feathering on sides of maxilla not reaching forward as far as the 
feathering at the base of culmen; no occipital crest. 
Type.—Anas valisineria Wilson. 
Remarks.—This monotypic group seems to be most nearly allied: to 
Aithyia, although by no means to be included in the same genus. It forms 
Isis (von Oken), 1822, Heft V, col. 564. 
“pict, Sci. Nat., rev. ed.; 1, 1916; suppl, p. 71. 
*Isis (von Oken), 1828, Heft III-IV, col. 359. 
4Nat. Hist. and Classif. Birds, II, July 1, 1837, p. 368. 
5Shaw’s Gen. Zool., XII, pt. ii, 1824, p. 187. 
*(Froriep’s) Notizen Gebiete Natur u. Heilk., XVI, No. 18, March, 1827, col. 279. 
