_Bill_ somewhat more produced and stouter than in _Caprimulgus_; _nostrils_ lateral and linear; _rictus_ entirely devoid of bristles, but furnished with short, weak, divided and branching hairs; _wings_ longer and more powerful than in _Caprimulgus_; first and second quills equal and longest; _tail_ moderately long and nearly square; _tarsi_ stout, and clothed anteriorly for their whole length; _toes_ short, thick and fleshy; outer ones equal, and united to the middle one by a membrane for more than half their length; nail of the middle toe strongly pectinated on the inner side. This genus, so far as is yet known, comprises but two species, both of which are natives of and confined to Australia. They differ considerably in their habits from the true _Caprimulgi_. Their wing-powers being enormous, they pass through the air with great rapidity, and while hawking for insects during the twilight of the early dawn and evening, they make the most abrupt and sudden turns in order to secure their prey. Like the typical _Caprimulgi_, they rest on the ground during the day. In every instance in which the site employed for incubation has been discovered, a single egg only has been found; it is deposited on the bare ground, and differs from those of the other _Caprimulgi_ in being much more round in form, and of a dull olive-green spotted with jet black. The members of this genus are very nearly allied to the _Lyncorni_, a group of birds inhabiting the Indian Islands. 46. Eurostopodus albogularis Vol. II. Pl. 7. 47. Eurostopodus guttatus Vol. II. Pl. 8. _Fichtel’s Goatsucker_, Lath. Gen. Hist., vol. vii. p. 345. Genus CAPRIMULGUS, _Linn._ Europe, Asia and Africa are the great strongholds of the members of this genus as at present restricted. A single species only has yet been discovered in Australia, where it frequents the northern or intertropical parts of the country. 48. Caprimulgus macrurus, _Horsf._ Vol. II. Pl. 9. This bird is found in Java, and I believe in Southern India. Family HIRUNDINIDÆ, _Vig._ Genus ACANTHYLIS, _Boie_. A group of birds possessing enormous powers of flight, and the members of which are distributed over the Indian Islands and Asia; the form is also found in Africa and in America, but in those countries the species are fewer in number: one species only has yet been discovered in Australia. 49. Acanthylis caudacuta Vol. II. Pl. 10. A migratory bird in most parts of Australia, but whence it comes or whither it goes has not yet been ascertained; of its nidification also nothing is known.