4QO 



THE BIRDS 



xvi. 31 



31. Other receptors 



The corpuscles of Grandry in the bill of ducks and other birds are 

 probably touch receptors, comparable to Meissner's corpuscles in 

 mammals. The corpuscles of Herbst, found in the dermis elsewhere in 



Fig. 301. a. Diagram of section of bird's ear. 



b.m. basilar membrane; col. columella; ex. extra-columella; E.t. Eustachian tube; 



f.r. round window; h.c.C. hair-cells of Corti's organ; h.c.l. hair-cells of lagena; sacc. 



sacculus; s.t. scala tympani; s.v. scala vestibuli; t.m. tectorial membrane; t.v. tegmentum 



vasculosum; tym. tympanic membrane. 



b. Diagram of section across cochlea of a bird. 

 G.cochl. cochlear ganglion; s.m. scala media; other lettering as in A. (From Pumphrey, 



after Satoh.) 



the body, resemble Pacinian corpuscles. They may be receptors for 

 vibration and are numerous in certain situations, for example in the 

 feather follicles, the beak, between the tibia and fibula, and in the tip 

 of the tongue of a woodpecker. 



Chemoreceptors for taste and smell are little developed. There are 

 few taste-buds on the tongue. The nasal cavity is large but the 

 olfactory epithelium restricted. It is doubtful whether most birds use 

 the nose as a distance receptor; they may use it to test air coming from 

 the internal nostril. In kiwis, however, which are nocturnal and terres- 

 trial, the olfactory sense is well developed. 



