Genus NYCTIDROMUS, Oould. 
Characteres Generici. 
Rostrum mediocre, ad basin latissimum, hiatu amplissimo, rictu setis elongatis instructo. Nares sub-hasales, elevata, 
transversim subovales, aperta. Alse mediocres, remige tertio cateris prastante . Cauda elongata, ampla, subrofundata. 
Tarsi nudi, elongati, antice scutellati. Digitorum externus et internus breves, intermedius elongatus, ungue pectinato ; 
digitus posticus liber, parvus, et ungue parvulo instructus. 
NYCTIDROMUS DERBYANUS, Gould. 
Nyct. fronte, vertice, nucha, et regione interscapulari cinerescentibus, minutissime nigro punctatis; vertice et ntichli lined 
irregulari nigrd ornatis ; genis, plumis auricularibus, mentoque rufo- fuscis, hoc obscure nigro fasciato, lined cervind ab 
angulo oris ; ala tectricibus rufo, cervino, nigroque ornatis ; primariis ad basin nigrescentibus, rufo fasciatis, in medio 
albis, ad apicem nigrescenti-fuscis ; secondariis rufo fuscoque fasciatis ; scapularilus rufis, nigrescenti punctatis et 
lineatis necnon cervino-margiiiatis ; dorso imo, rectricibusque cauda duabus intermediis sordide cervinis, nigro pun- 
ctatis, et obscure fasciatis; rectrice externd utrinque nigrd, intus albo marginatd; reliquis albis; corpore subtus cervino, 
fusco fasciato ; pectore superiore plagd albd semidivisd ornato ; rostro pedibusque brunneis. 
Long. tot. 12 une. i rostri, If; ala, 7 ; cauda, 7 ; tarsi, 1-^. 
Forehead, top of the head, hack of the neck, and space between the shoulders pale grey, minutely pencilled with 
black, and with an irregular mark of black from the top of the head along the back of the neck ; sides of the 
face, ear-coverts, and chin rufous brown, the latter obscurely barred with black, a stripe of bufP running from 
the angle of the mouth ; wing-coverts mottled rufous, buff and black, each feather largely tipped with buff ; 
base of the primaries black, banded with rufous, to which succeeds a central band of white, the remainder being 
browiiish black ; secondaries alternately with brown and I’ufous ; scapularies rufous brown, fi-eckled with 
black, bounded externally with blackish bromi, and margined with buff ; lower part of the back and central 
tail-feathers dirty buff, obscurely freckled and baiTed with blackish brown ; outer tail-feather on each side 
black, with a white internal margin ; the remaining tail-feathers white, under surface buff, barred with brown ; 
a white semidivided gorget across the chest ; bill and feet brown. 
Nyctidromus Derbyanus, Gould, in Proc. of Zool. Soc. Part VI. 1838. 
The members of this group are confined to South America ; they run much on the ground, and are remark- 
able for the great dilatation of the base of the under maxillary bones. There are at least ten species of this 
peculiar form, among which has hitherto reigned the greatest confusion. The present bird, which I have 
reason to believe has been confounded with other proximate species, I venture to distinguish by the title of 
Derbyanus. 
The figure is of the natural size, and is taken from a fine example kindly lent to me by the Earl of Derby. 
