. The Cambridge natural history. Zoology. particular function to any of them, except it he to tlie sensory hairs. These are seated on various parts of the body. The chitinous covering, being a dead, hard substance, has no nerves distributed in it, but it is pierced with orifices, and in some of these there is implanted a hair which at its base is in connexion with a nerve; such a structure may pos- sibly be sensitive not only to contact %gMSW^'^-?j!i^igg^:, n. with solid bodies, but even to vari- _ ^, - ., ,. , ,. r ous kinds of vibration. We give a Fig. 67.âijongitudmal section oi ° portion
. The Cambridge natural history. Zoology. particular function to any of them, except it he to tlie sensory hairs. These are seated on various parts of the body. The chitinous covering, being a dead, hard substance, has no nerves distributed in it, but it is pierced with orifices, and in some of these there is implanted a hair which at its base is in connexion with a nerve; such a structure may pos- sibly be sensitive not only to contact %gMSW^'^-?j!i^igg^:, n. with solid bodies, but even to vari- _ ^, - ., ,. , ,. r ous kinds of vibration. We give a Fig. 67.âijongitudmal section oi ° portion ot caudal appendage of figure (Fig. 67) of some of these hairs ^. ^X^;^^^ on the caudal appendage of a cricket, dermis ; n, nerve ; h}, integu- after Voill Eath, The Small hairS Oil mental hairs, not sensitive ; Jr. ,â , , p p ,^ -i â¢,â ⢠,i â ordinary hair; A^ sensory hair ; ^^e OUter Surface of the chltni m thlS h*, "bladder-like hair; .% sense- figure have no sensory function, but each of the others probably has; and these latter, being each accompanied by a different structure, must, though so closely approximated, be supposed to have a different function ; but in what way those that have no direct connexion with a nerve may act it is difficult to guess. The antennae of Insects are the seats of a great variety of sense organs, many of which are modifications of the hair, pit and nerve structure we have described above, but others cannot be Isrought within this category. Amongst these we may mention the pits covered with membrane (figured l;iy various writers), perforations of the chitin without any hair, and membranous bodies either con- cealed in cavities or partially protruding therefrom. Various parts of the mouth are also the seats of sense organs of diiTerent kinds, some of them of a compound character; in such cases there may be a considerable number of hairs seated on branches of a common nerve as figured sck. -Longitudinal section of apex of palpus
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
