152 BIRDS OF INDIA. 



combined in some cases with an extensile tongue, or in others with 

 a bruslied tongue, and in most with a peculiarly-shaped bill, and a 

 small gape, indicate a marked type. 



The Fissirosti'es and Scansores can thus be in general at once dis- 

 tinguished from each other, and from the Deniirostres and Conii^oft- 

 tres by the form of the feet, and from the Tenuirostres by the bill 

 and feet combined ; whilst these three last families are best dis- 

 tinguished, inte?' se, by the form of the bill, aided, in some cases, 

 by other points of structure or habits. 



The student of Ornithology, however, must not expect that these 

 tribes, or indeed most of the families, or other divisions, can be 

 rigorously defined, and a full examination of every part of a bird's 

 structure, its habits and nidification, must often be held, before its 

 place in a natural system can be determined. All these tribes 

 exhibit relations, in some cases of affinity, in other perhaps of 

 analogy, with each other, and some indeed may be said to unite 

 by more or less imperfect links. Thus the Conirostres and Den- 

 iirostres appear to vuiitc by means of the Larks on the one side, 

 and the Pipits on the other; the Dcntiroslres perhaps unite with the 

 Fissirostres through the Eurylaiuii; the latter tribe with the Tenui- 

 rostres through the Humming hirds; the Tenuirostres to the Denii- 

 rostres by means of the Honey Eaters and Bulbuls ; the Fissirostres 

 to the Scansores through the Barbets ; the Tenuirostres to 

 the Scansores perhaps by the Creepers and Nuthatches, and 

 the Conirostres to the Fissirostres \\\xo\i^\ the Hornbills; and these 

 and other affinities will be pointed out under their respective heads. 



Some able Ornithologists separate the Parrots entirely from the 

 rest of the perching birds, making them into a distinct order, and 

 placing them at the head of the class, as parallel to the Monkeys 

 among IMammals. The propriety of this will be considered when 

 we come to the Scansores. They divide the rest of the perching birds 

 into two great groups, 1st, Oscines, or Passeres, or Cantores, or sing- 

 ing birds ; and 2nd, Volucres, Clamatores, or Strepitores, or Scree- 

 chers. The former, or singing birds, possess some additional tracheal 

 muscles, necessary for singing, and the latter want them. To 

 carry this dichotomous classification out to its full extent, as 

 some do, requires that the Swallows be separated from the 



