364 CLASS XVI. 



From this interweaving of the description of the skin and 

 feathers of birds we turn to the consideration of their organs of 

 sense. Taste is little developed in birds, and in most of the species 

 the tongue itself is quite inadapted to serve as an instrument of this 

 sense, being merely a horny covering of the two cartilages or bones 

 which lie side by side, or have coalesced, and which are attached to 

 the body of the tongue-bone in front [ossa lingualia s. eritoglossa) . In 

 the parrots however the tongue is thick and muscular, and beset with 

 some papillse at its base. It is muscular also in many water-birds, 

 as the ducks, where it is provided at the margin with stitF bristle-like 

 denticles, armed with rows of hard laminas, and covered at the base 

 with long soft papillae., in front of which is a large grooved tubercle. 

 In most birds the tongue serves merely for deglutition, or for seizing 

 the food, as in the*woodpeckers, where it can be extended far from 

 the mouth. The tongue-bone consists, in addition to the cartila- 

 ginous or bony nucleus of the tongue itself, which has been noted, 

 of a body mostly elongate, to which, at the back part, a stiliform 

 bone is usually attached [urohyale of Geoffroy), and of two long 

 horns, which are sometimes cartilaginous at the apex, and mostly 

 formed of two joints. In the woodpeckers and humming birds 

 these horns mount upwards upon the cranium and glide downwards 

 when the tongue is extended. The tongue of birds admits of great 

 motion as a whole from many extraneous muscles, as extension and 

 retraction; but it possesses little flexibility, and thus is not in a 

 condition to bring its surface into that variety of contact with the 

 food which is required for tasting. 



The organ of smell is more highly developed^. On the back of 

 the bill, at a greater or less distance from its point, mostly more 

 towards its base, are seen the two nostrils". Frequently these 

 apertures, in order that they may not be obstructed by sand or 

 other matters, are covered by bristles (stiff, imperfect feathers), 

 especially in those birds which pick their food from the ground. 

 The cartilaginous septum of the nasal cavities, that rests upon the 

 vomer, is perforated in some birds (??ares pervice). The nasal 



1 Scarpa De Auditu et OJfactu, pp. 77 — 85, Tab. in. ; compare also Harwood 

 System of Comp. Anat. and Phys. Cambridge, 1796 ; 4to, p. 25. 



2 In Sula alba, according to Nitzsch, they are entirely wanting, Jahresberidit der 

 Naturf. GeselUch. zu Halle, 1825, s. 23. Schlegel, however, found them in this bird, 

 but they cannot be perceived in Sula piscatrix and parva. Tijdschr. voor natuurl. 

 Geschied. en Physiol, ir. 1839, s. 168 — 172. 



