112 Proceedings of JiHliana Academy of Science. 



Tliis yciius in some respects resembles Aristoiictta, as for instance in the 

 much concave base of culmen. in wliich character it differs from all the 

 other groups here considered. It is, however, well differentiated from Aris- 

 tonettu, as may be seen from the diagnosis under that genus. 



The generic name Aythi/u Boie' is the earliest name applicable to this 

 group, but it is preoccupied by Acfhya Dumont,^ wliich is a synonym of 

 Aethia, the earliest name for the genus of Alcidae formerly known as Simo- 

 rhynchiis. The Aifln/a of Boie-' is. of (Mur.-e. nu-rely an emendation of Aiithyn 

 Boie. and is also preoccupied by Aclliya Dumont. Likewise, FtilU/uhi 

 Swainson,* the type of which by monotypy is Anas ferina Linnaeus, is pre- 

 occupied by Fiiligiila Stephens."' The name Aithyia Gloger," proposed as an 

 emendation for Aythya Boie. is, however, by virtue of its additional syllable, 

 a different word, therefore tenal)le 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). 



Aristoiictta BAIRD. 



Aythyia BONAPARTE. Compt. Bend. I'Acad. Sci.. XXXVIII No. 14, 

 April 10, 1854, p. (5(i4 (type liy monotypy. Anas {■aJi^invria Wilson) (nee 

 Aithyia Gloger). 



Aristonetta BAIRD. Rep. and Explor. Surv. R. R. Pac, IX, 1858, p. 793 

 (in text) (type by original designation and monotypy. Anas valisiiieria 

 Wilson). 



Anthya LE MOIXE, Ornith. Canada, pt. 1. 18(j(», p. !X) (type. Anas va>- 

 lisineria Wilson ) . 



Diaynosis. — Similar to^Aithyia. but length of expused culmen about ecpial 

 to length of inner toe with claw, m<n-e than twice the height of bill at ex- 

 treme base, and about 3 times the greatest width of l)ill ; 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 3 3/4-3 4/5 times the length of the exposed culmen; 

 bill much flattened terminally, its width near end not more than its width 

 at base, r.sr.r.Ty less; tip of bill rounded; width of bill at posterior end of 

 nail 2 1/5 times 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 11/4 — 

 times the greatest width of bill : base of culmen deeply concave ; length of 

 exposed culmen 2 2/5 times the height of bill at extreme base, about 3 

 times the greatest width of bill, iind equal to the length of inner toe 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. 



I'ype. — Anas vaUsineria 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 f(n-ms 



ilsis (von Oken), 1822, Heft V, col. 564. 



2Dict. Sci. Nat., rev. ed., I, 1916. suppl., p. 71. 



='Isis (von Olion), 182S, Ileft III-IV. col. :;',<). 



^Nat. Hist, and Classif. Birds. II, .Iiil.v 1, ls:i7. ]>. ;!()S, 



^Shaw's Gen. Zool., XII, pt. ii, 1824, p. 1S7. 



"(Froriep's) Notizcii Ocbi.-te iNatur ii. llcilk.. XV-I. Ni 



