ORGAN OF TASTE IN BIRDS. 129 



ends, giving a closer grasp of the perch or the prey, and a firmer 

 tread of the hard ground. The digital villi are unusually long in 

 the Capercailzie ( Tetrax urogallus) enabling it to grasp with 

 more security the frosted branches of the NorAvegian pine-trees. 

 The integument of the toes is sparingly supplied with nerves in 

 all Birds ; but it may be supposed that the more delicately 

 papillose slender flexible digits of the smaller nidificators guide, 

 by sensations analogous to touch, in the complex interweavings 

 of the materials of such beautiful structures as the pensile, domed, 

 and otherwise adaptively perfected nests fabricated by the Tailor- 

 birds, and most Cantor es. 



Actions indicative of tactile exploration have hitherto been 

 observed to be performed by the bill, exclusively, in Birds. 

 Although in most of the class the horny sheath of the bill be 

 hard, sensitive filaments of the ' fifth' nerve (fig. 53, c) are trace- 

 able to the papillose extensions of the vascular formative surface 

 into such sheath. In the Lamellirostrals the substance of the 

 sheath is softer and its marginal lamellae are more abundantly 

 supplied by the ^ fifth : ' from the tactile and selective actions of 

 the bill in those Birds, they are called ' Sifters.' The soft and 

 slightly expanded end of the long and slender bill of some GrallcR 

 (Woodcocks, Snipes) is so organised for touch, that it is used as 

 a probe in soft ground to detect the worms, grubs, and slugs that 

 constitute their food. 



Peculiar productions of integument, devoid of feathers, such as 

 the ^ cere ' of Birds of Prey, the ' wattles ' of the Cock, and of 

 species of Philedon, Glaucojns, and other so-called ^ wattle birds,' 

 the cephalic caruncles of the King Vulture and Turkey, &;c., have 

 been loosely cited amongst ^ organs of touch.' 



§ 141. Organ of Taste. — The gustatory sense is very imper- 

 fectly enjoyed in Birds, which, having no manducatory organs, 

 swallow the food almost as soon as seized. The tongue is 

 organised chiefly to serve as a prehensile instrument, and its 

 principal modifications will be treated of in Chapter XVII. 

 It is generally sheathed at the anterior part with horn, and is 

 destitute of papillae except at its base, fig. 51, o, near the aperture 

 of the larynx, /; these papillce are not, however, supplied by a 

 true gustatory nerve, but by filaments of the glossopharyngeal. 

 No branch of the fifth pair goes to the tongue ; but the mem- 

 brane of the palate and fauces is so supplied that the sapid 

 qualities of food may be there appreciated. 



The tongue is proportionally largest and most fleshy in the 

 Parrot tribe, and the food is detained in the mouth longer in 



VOL. II. K 



