The true Cranes are birds of large size with long necks and legs but with the bill only equal to, or but little longer than, the head. The nostril is enclosed by a membrane on the posterior side and is placed in the base of a groove, which extends about half-way up the middle of the mandible. The tail has twelve feathers and the wing eleven primaries ; the tracheae pass into a hollow space between the long walls of the sternal keel and are more or less convoluted. There is a small aftershaft.
Our Indian Cranes were divided by Sharpe into four genera - Grus, Sarcogeranus, Antigone and Anthropoides. The name Grus is tenable and has not to give way to Megalornis*, whilst the differences between this and Sarcogeranus seem hardly generic. On the other hand, Antigone, not recognized by Blanford, is now generally accepted as sufficiently well denned to constitute a good genus.
Cranes are almost cosmopolitan in range, three genera and six species being found in India.
Key to Genera.
A. Crown of head bare ; sides of head and upper neck feathered…………GRUS, p. 49.
B. Crown of head bare : sides of head and neck not feathered…………ANTIGONE, p. 54.
C. Crown of head feathered…………ANTHROPOIDES, p, 57.