. Chambers's encyclopaedia; a dictionary of universal knowledge. ids is especiallytrue of the are large andjiowerful, and can►e rapidly accom-moilated to differ-ent difler only inminor points fromthose of any verte-brate. Tlie formis far from spheri-cal, the front portion being protrude<l. and to ac-rtain extent constricted otV from tlie ball l» special ring of .small Ixtny plates nrotects the tliis anterior |M)rtion. A comb-like nutritive fold(pecten), absent only in the kiwi, orojects fromWhind into the posterior chamber of the eye.
. Chambers's encyclopaedia; a dictionary of universal knowledge. ids is especiallytrue of the are large andjiowerful, and can►e rapidly accom-moilated to differ-ent difler only inminor points fromthose of any verte-brate. Tlie formis far from spheri-cal, the front portion being protrude<l. and to ac-rtain extent constricted otV from tlie ball l» special ring of .small Ixtny plates nrotects the tliis anterior |M)rtion. A comb-like nutritive fold(pecten), absent only in the kiwi, orojects fromWhind into the posterior chamber of the eye. Athird transparent eyelid «tr nictitating membrane( not restricted to birds) is conspicuously developed,an<l ianl)e drawn like a .screen across the eye. Itlies hidden in tlie anterior corner. Tear and otherglands are pies«nt. The ear ditlers markedly fromthat of niammals in the absence of any external Fig. fi.—Brain of Pigeon :a, fore brain; h, !» llna : .-. opticlobes; bcnly ; i, j. Fig. 7.—Head of Falcnn, showing beak, nostril, eye, andear ; opening exposed by reiuuval of feathers. portion. In the birds of prey, however, a memhran-ous flap is nresent. The external opening is usuallysurrounded liy a circle of tine hair-lilve feathers. Asregards ear lH)nes, only one (the columella) is pres-ent, ami ill this particular also the bird ear ditlersfrom that of mammals. The snail-like coil of theear-cavity (tiie cochlea) is also much sim|)ler. The( Eustachian) tul>es which lead from the ear-apertureilown to the mouth, unite before they open intothe latter. The nostrils are usually situated atthe of the beak, but may occur furtherforward, and in the kiwi are .situated at thevery tiji. In some cases they are guanled bybristles, in other jirolonged into a tube, butare usually simple apertures. The nasal cavitiesmay communicate with one another, and containtwo or more gristly or bony scrolls. A gland is present. The sense of smell isiiiiilo
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Keywords: ., bookcentury1900, bookdecade1900, bookpublisherlondo, bookyear1901
