110 Procccdi'iKjs of Indhina Academy of Science. 



J'crissoiicHd. .i^t'ii. iiov.' 

 Diagnosis. — Similar to Xi/roca, hut longtli of exposed culmen equal to 

 length of inner toe with claw (instead of decidedly shorter) ; feathering on 

 •sides of maxilla extending forward as far as the feathering at the base of 

 the culmen; anterior outline of feathering at tlie base of culmen broadly 

 convex ; and length of wing only about 4 times the length of exix)sed culmen. 

 Description. — Wing 4 times the length of exposed culmen ; bill relatively 

 little flattened terminally, its width near end abbut 1 1/S times its width 

 ar base, its tip rounded, and its width at posterior end of nail about 2 times 

 the length of the nail; tip of maxilla much luiokcd : nail (it bill rather wide 

 and subtriangular ; height of bill at extreme base. 1 1 /s times its greatest 

 width; base of culmen not deeply concave; exposed culmen about 21/4 

 times the lieight of bill at extreme base, 2 2/5 times the greatest 

 widtli of bill, and equal to the length of inner toe with claw ; anterior out- 

 line of feathering at base of culmen broadly convex; the feathering on 

 sides of maxilla reaching forward as far as that at the base of culmen; a 

 short, bushy occipital and coronal crest. 

 Type. — Anas coUnris Donovan. 



NemarJcs. — Mr. N. Hollister's excellent iirticle on this species- serves but to 

 emphasize the distinctness of this duck from its Old World relatives. As 

 the characters that we have above given show, this species forms one of 

 the most trenchantly distinct groups among the genera allied to Nyroca. 

 Most of its distinctive characteristics are here for the first time presented, 

 and it is quite evident that had tliey been appreciated before, the bird 

 would long ago liave figured as the type of a new genus, a fate that it seems 

 to have escaped until now. In addition to the other characters by wliicli it 

 is readily and variously distinguishable from each of the generic groups here 

 treated, it differs from all of these in the shape of the frontal feathering at 

 the base of the culmen. and in the relati\e anterior extent of the feathering 

 on the sides of the maxilla ; and also, from all but ArlstoneUa. in having the 

 exposed culmen equal to the length of the inner toe with claw. Notwith- 

 standing its coloration, it is full.v as well differentiated from Fulicjula as 

 from Nyroca, as the following differences from the former sliow : wing only 

 4 times the length of exposed culmen ; lieight of bill at extreme base much 

 more than the greatest width of bill; length of exposed culmen about 2 1/2 

 times the greatest width of bill ; exposed culmen equal to inner toe with 

 claw; anterior outline of feathering at the base of culmen convex, that on 

 sides of maxilla reaching as far forward as that at the base of culmen: 

 occipital crest short. 



The only species assignable to this group must now lie called Peri.s.soiKlht 

 collar hs ( Donovan ) . 



Aitlipia GLOGER. 



Aythya BOIE, Isis (von Oken), 1822. Heft V. col. 564 (type by subse- 

 quent designation [Degland. Ornith. Europ.. II, 1849, p. 455.], Anas fcrina 

 Linnaeus) (nee Acihjta Dumont. (piae Acfhia Merrem [Alcidae]). 



Aithyia GLOGER. (Froi-lep's) Xotizen (ieliiete Natur u. Ileilk.. XVI. No. 

 18, March, 1827. col. 270 (noni. emend, prd Ai/lln/a I'oie: type. th(>refore, 

 A7ias fcrina Linnaeus). 



mirabilis ; netta, anas. 

 -The Auk, XXXVI, No. 4, October, 1919, pii. 4UO-4G;!. 



