Order XV. PYGOPODES.
The last order of Indian birds to he described contains the Loons or Divers (Colymbidae) and the Grebes (Podicepidae). The former of these families is, so far, represented in India only by the occurrence of a single specimen of the Black-throated Diver, Colymbus arabicus. The two families, though superficially not unlike, have the feet utterly different and by some systematists are still kept in separate orders.
In this Order the skull is schizognathous and holorhinal; the nostrils pervious ; basipterygoid processes wanting; the plumage is very short and dense, the lower plumage especially having remarkable wet-resisting properties; an aftershaft is present; the feathering of the neck is continuous; the wing is aquincubital; an oil-gland is present and tufted ; caeca are present; the posterior border of the sternum has one incision on each side; the flexor tendons are the same as in the Anseres.
The anterior proximal (cnemial) process of the tibia is greatly developed, being very high and pyramidal; the legs are situated very far back, the tarsus is strong and compressed, the tail is very short and completely concealed by the coverts.
Key to Families.
A. Toes furnished with broad lateral lobes not divided into sections………… Podicepidae, p. 476.
B. Toes completely connected by webs reaching the tip of each ………… Colymbidae, p. 485.