Size small. Casque either small, compressed, and terminating anteriorly in a point or entirely wanting. Bill much curved, carinate above. Tail graduated in all Indian species. Crest moderate. Plumage of Indian birds chiefly grey.
I refer to this African type (which is identical with Tockus of Lesson) the three small Hornbills of India and Ceylon. By Jerdon, Hume, and others they have been divided into two genera; by Ogilvie Grant they have been united and placed in a genus apart from their African relatives on account of their more wedge-shaped tail. This distinction I find does not hold good; neither Indian nor African forms are all alike in the relative lengths of the rectrices. I do not place the Indian L. birostris in a separate genus from the other two species, because the type of Lophoceros, the Abyssinian L. nasutus, closely allied to the Indian forms but without a casque, is only distinguished from the S. African L. epirhinus by the presence in the latter of a small casque, precisely like that of L. birostris, but smaller. It is clear that in this group of small Hornbills the presence or absence of a small casque is not a generic character.
The genus Lophoceros comprises 17 African species ; two occur in the Peninsula of India and one in Ceylon. None extend farther east.
Key to the Species.
a. A small casque, pointed in front ……………….L. birostris, p. 155.
b. No casque.
a1. Nostrils in an elongate groove……………….L. griseus, p. 156.
b1. Nostrils round, not in a groove……………….L. gingalensis, p. 157.