. Cassell's book of birds . fulfil in some degree the purposes ofa hearing trumpet. (See Fig. 8.) In such species the sense of hearing is exquisitely developed. In the generality of birds the sense of taste can scarcely be said to exist. The manner inwhich they obtain and swallow their food precludes the possibility of enjoyment from this source, sothat their tongue is in many cases appropriated to some totally different use. In by far the greaternumber the tongue is small, thin, and cartilaginous ; the extremity is flat, and incapable of beingprotruded beyond the bill. (See Fig. 9.) There are
. Cassell's book of birds . fulfil in some degree the purposes ofa hearing trumpet. (See Fig. 8.) In such species the sense of hearing is exquisitely developed. In the generality of birds the sense of taste can scarcely be said to exist. The manner inwhich they obtain and swallow their food precludes the possibility of enjoyment from this source, sothat their tongue is in many cases appropriated to some totally different use. In by far the greaternumber the tongue is small, thin, and cartilaginous ; the extremity is flat, and incapable of beingprotruded beyond the bill. (See Fig. 9.) There are, however, great varieties in the construction ofthis organ, a few of which will require our notice. The tongue of the parrot, although its substance is not so fleshy, has some resemblance to thatof man, and it is probable that this is one of the circumstances enabling these birds to imitate thehuman voice with so much facility. In the family of the toucans and some others, the tongue, without being extensible, is fully as. Fig. 8. — EXTERNAL EAR OF A YOUNG OWL. a, the Upper Part of the Head, partially denuded of feathers ; /, the Beak ;d, the Eye ; e, e, f, Marginal Fold of Skin surrounding a cavity, theinterior of which somewhat resembles the folds of the human ear;g, Auditory Passage leading to /i, the Drum of the Ear {membranatympani). editors introduction. II long as the largely developed bill, and, moreover, its sides are fringed like those of a feather. Atongue of this description may probably be endowed with some delicacy of taste, enabling these birdsto appreciate the flavour of the fruits on which they feed. Birds of the duck family have the largest tongues. Owing to its fleshy appearance it more nearlyresembles the human tongue than even that of the parrot. Birds of this family discriminate theirfood not by sight, but by the delicate sense of touch with which their tongue is endowed. Theythrust their bill into the mud, and from the mouthful thus obtained select, by
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Keywords: ., bookauthorbreh, bookcentury1800, bookdecade1870, booksubjectbirds
