Comparative zoology, structural and systematic. For use in schools and colleges (1880) (20047992514)

Title: Comparative zoology, structural and systematic. For use in schools and colleges
Identifier: comparativezoolo00orto (find matches)
Year: 1880 (1880s)
Authors: Orton, James, 1830-1877
Subjects: Zoology
Publisher: New York, Harper and brothers
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries



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YVCwiiHif'^ it produces a focus like a lens lens, is the pigment, having a minute ap- erture, or " pupil." Next (in place of the "vitreous humor" of Vertebrates) is a con- ical tube â one for each facetâwith sides and bottom lined with pigment. These tubes converge to the optic ganglion, the fibres of â w^hicli pass through the tubes to the cor- nea."'^ Vision bj such a compound eye is not a mosaic; but each ocellus gives a complete image, although a different per- spective from its neighbor. The mul- tiplied images are re- duced to one mental stereoscopic picture, on the principle of single vision in our- selves. The eyes of the r, ,.o o X- OTT ^ .. ^ Cuttle-fish are the Pig. 153.âSection of Hiiman Eye: a and 6, upper and lower lid; c, conjunctiva, or mucous membrane, largest and the mOSt lining the inner surface: d, external membrane: «. ^ -r sheath of optic nerve; /, n, muscles for rollinjr the perfect amOUg lnver- eye up or down ; k, sclerotic; i, transparent cor- , ^ ^ q-,V nea; .7, choroid ; fc, i, ciliary muscle for adjusting teoratCS. -^-ll^V TC- the eye for distance ; w, iris and pupil;«, canal; cpmhlp tbp OVOS of 0, retina; ,s, vitreous humor; ^crystalliue; v.au- SCâ¢'^^^ "^"^ ^3^^ "^ terior chamber; a;, posterior chamber. hio-hcr auimals in having a crystalline lens with a chamber in front (open, FiQ. 152.âEye of a Beetle (Melolontha): A, section; a, optic ganglion ; &, secondary nerves ; c, retina; d, pigment layer; e, proper optic nerves; B, group of ocelli; /, bulb of optic nerve; g, layer of pig- ment ; h, vitreous humor ; i, cornea.
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