ORDER VI. The PASSERES, have a conical sharp-pointed BILL; and the nostrils are oval, wide, and naked.—This order contains 15 genera, viz. Caprimulgus, Alauda, Columba, &c. See these articles.
The generic characters of this class are taken from peculiarities in the bill, the nostrils, the tongue, the feet, the feathers, the face, the figure of the body, &c.
The characters which serve to distinguish the species are very various: For example, the colour of particular feathers or parts of feathers; crests of feathers on the head, disposed in different manners; the colour of the cere or wax; the colour of the feet; the shape and length of the tail; the number, situation, &c. of the toes; the colour and figure of the bill; &c.
The Third Class, AMPHIBIA, is divided into four ORDERS.