Bill long and slender, culmen considerably curved towards tbe tip ; nostril in a groove, much farther from the base of the bill than in Sterna; tarsus short, much shorter than the middle toe without claw; feet large, toes fully webbed. Wing long, first quill longest; tail long, cuneate, the third or fourth pair of feathers from the outside longest, considerably exceeding the outer feathers. The whole plumage is very dark.
The Noddies, as they are called, are a group of tropical oceanic birds allied to the Terns, but having a much slower, heavier flight and very different habits. They live in the open sea and settle on the water to feed on floating mollusca or dead fish, or offal. In the British Museum Catalogue they are divided into two genera, Anous and Micranous; but the differences are not great, and it is more convenient to class the two species found in Indian seas in one generic group.
Key to the Species.
a. Fourth pair of rectrices from outside longest; bill stout, angle of lower mandible nearer to tip than to gape; crown grey …………………………A. stolidus, p. 325.
b. Third pair of rectrices from outside longest; bill slender, angle of lower mandible equi-distant from tip and gape; crown white…………………………A. leucocapillus, p. 326.