Australian Birds in the Collection of the Linnean Society. 195 
Vibrisse mastacales ad apicem simplices, ad basin pecti- 
nate ; capistrales numerose, longissimæ, porrectæ, utrin- 
que pectinatæ. Nares in medio rostri posite, lineares, 
obliquæ, subpatulæ, posticè angustiores. 
Ale breves, rotundatæ. Remiges prima et sexta ferè æquales 
brevissimæ, secunda et quinta æquales longiores, tertia et 
quarta æquales longissimæ ; secundæ pogonio externo levi- 
ter, tertiæ ad quintam inclusam pogoniis externis profundè 
emarginatis: secundæ ad quintam inclusam pogoniis inter- 
nis emarginatis. 
Pedes congrui. Tarsi elongati, subgraciles, compressi, nudi. 
Digiti liberi, subgraciles, ferè æquales. Hallur longus, 
debilis. Ungues compressissimi, medio integro. Acrotarsia 
acropodiaque scutulata; horum scutis confertis approxi- 
 mantibus. | : | 
Cauda mediocris, rotundata. 
The .perfection of the family of Caprimulgidæ may be con- 
sidered as most fully exhibited in the true Caprimulgus, Auct., 
of which the common European species is an adequate example. 
In that genus, which forms part of the typical group of the 
Fissirostral tribe of the Insessores, the chief characters that dis- 
tinguish the birds of the tribe are strongly developed, namely, 
the powers of flight and of receiving their food within the wide 
gape of their bill when on the wing. The chief strength of the 
bird is thus centred in the wings and the rictus of the bill; and 
a proportional deficiency takes place in those other members 
which are less necessary to it in the performance of its peculiar 
functions. The bill itself is feeble, and apparently useless in 
securing its prey, which object is effected chiefly by a viscous 
exudation within the gape, and a regularly disposed network of 
strong bristles, which externally margins the rictus. The legs 
j 2c2 also 
