The last order of Indian birds to be described contains the Grebes, with which the Loons or Divers (Colymbidae) are usually, though not always, associated ; the latter are not represented in India, being restricted to more northern regions. The Auks (Alcidae), originally comprised in the Pygopodes by Illiger, are now by most ornithologists regarded as allies of the Gulls.
In the present order the skull is schizognathous and holorhinal; the nostrils pervious ; basipterygoid processes wanting. Plumage very short and dense : an aftershaft is present, the feathering of the neck is continuous, the wing is aquincubital; the oil-gland tufted. Caeca are present. Posterior border of sternum with one incision on each side. Plexor tendons as in 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 compressed. Bill straight and pointed.