AKT.19 CONCERNING BIRDS ' TONGUES GARDNER 21 



Lucas ^^ pointed out in the case of Collocalia (fig. 85, after Lucas) 

 while others have a longer, more slender tongue somewhat curled 

 as in the tree swift Macropteryx coroTiata (fig. 82). 



The humming birds (Trochilidae), however, have most character- 

 istic tongues, which are distinct from any others in the class of 

 Birds. The cartilaginous portions of the ceratohyals are divided in 

 the anterior half of the tongue to form separate shafts. These are 

 invested with a membranous covering which is expanded as a lateral 

 flange at the tip, but which inrolls as the base of the tongue is 

 approached to form a rolled membranous tube on each side. (See 

 fig. 86, Calypte anna.) 



It is not composed of parallel muscular tubes, as has often been 

 described, for the cartilaginous shafts of the tongue are solid ; but it 

 is the inrolled fringe of membrane along the lateral margins of 

 these shafts that make up the capillary tubes. This is an entirely 

 different condition than prevails in the passerine flower frequenters 

 where two or more muscular tubes are formed by splitting and curl- 

 ing of the body of the tongue itself. 



It is very elastic in the humming birds and capable of great pro- 

 trusion, the hyoid apparatus also being especially long to permit of 

 this action. 



This is a most characteristic organ which readily identifies any 

 bird possessing it as a member of this family, and while markedly 

 modified in response to flower-feeding habits is nevertheless dis- 

 tinctive of the group and hence of taxonomic value. 



The trogons have flat, heavy tongues supplied with numerous 

 sjDines and with a cornified tip. There is a central groove bordered 

 by raised margins, a condition most unvisual and not seen elsewhere, 

 except in members of the next group. {Pyrotrogon neglectus, fig. 21.) 



The puff-birds (Bucconidae) have odd flat tongues that about the 

 center widen to form prominent shoulders, gradually narrowing 

 from this point anteriorly to a blunt tip. The surface is flat except 

 in the anterior third, where a groove is seen, the margins of which 

 are raised forming parallel prominent ridges on the surface. This is 

 well illustrated by Bucco Mcinctus (fig. 83) and is also seen in 

 Notharchus dysoni and Nystalus maculatus striatipectus. These are 

 very unusual appearing structures the exact functions of which are 

 not known. 



The Ramphastidae are characterized by exceptionally odd feath- 

 ered tongues which are long and narrow and with deeply incised 

 lateral margins forming anteriorly directed laminae. The fleshy 

 hyoidean portion forms but a small part of the tongue posteriorly 

 while anterior to this it becomes thin, horny, and translucent. This 



" The Auk, vol. 13, pp. 109-115, April, 1896. 



