1012 



REPOET OF NATIONAL MUSEUM, 1895. 



individuals where the ends of the hyoid curl about the eyeball instead 

 of dipping into the beak, but this is found less often than the other. 

 The tongues of some species— the ilicker, for example— have but one or 

 two barbs at the tip, others have half a dozen, and still others twenty 

 to thirty, the barbs becoming finer as they become more numerous. 

 Finally, in the sapsucker the barbs have degenerated into stiff hairs, 

 which, instead of raking backwards, stand out from the side like the 

 bristles on a chimney cleaner. 



It is interesting to note the modifications 

 by which the hyoid is made effective as a 

 probe, or spear, since for this last purpose it 

 should be as rigid as possible. The two fore- 

 most i^ieces of the hyoid are much reduced 

 in size, and are united to form a leaf-shaped 

 Ijoint, although we have a hint, in the pres- 

 ence of a groove or perforation, that this 

 point really consists of two bones. The shaft 

 of the spear is partly formed by the long 

 and slender basihyal and partly by the two 

 ceratobranchials, which are brought close 

 together Avhen the tongue is protruded. 

 These last are attached directly to the rear 

 of the basihyal — an arrangement which in- 

 creases the power of the thrust. (See fig. 1 e.) 

 The ducks have one general type of tongue, 

 and while the mergansers differ much from 

 the broad-beaked species, as might imturally 

 be expected, it is possible here, as among the 

 woodpeckers, to see underlying the modifica- 

 tions that all are but variations of one type. 

 The sides of the tongue are provided with 

 several series of overlapping bristles, inter- 

 spersed with tooth-like projections, which are 

 simply bristles on a large scale, or bristles 

 fused together, as the horn of a rhinoceros 

 is composed of agglutinated hairs. There 

 may be only three or four of these teeth 

 toward the base of the tongue, as in the ring- 

 necked duck (fig. 8 a), or they may prejionderate, as in the Canada goose, 

 a species in which they reach the maximum of development, the tongue 

 being armed on either side with a row of saw-like teeth. Finally, there 

 may be no teeth at all, as in the hooded merganser (fig. 8 b), whose slen- 

 der, gutter-shaped tongue bears on its edges only a series of bristles 

 pointing obliquely upward. Ordinarily they point obliquely downward, 

 suggesting a straw-thatched roof, but in any case their apparent func- 

 tion is that of a strainer to aid in securing food. 



