Archive image from page 866 of The cyclopædia of anatomy and. The cyclopædia of anatomy and physiology cyclopdiaofana03todd Year: 1847 777 Fig. 428. Brain and organ of vision of a Cyclops kitten, at the full period of gestation. Seen from below. (Natural size.) a, organ of vision, single, and of great dimensions ; b, b, cerebral hemispheres seen from below ; d, d, tubercula quadri- gemina ; c, optic nerve, single, and of great size. foetuses consists in the total absence of the organ of smell, in consequence of which de- ficiency the symmetrical organs at either side become united in the midd
Archive image from page 866 of The cyclopædia of anatomy and. The cyclopædia of anatomy and physiology cyclopdiaofana03todd Year: 1847 777 Fig. 428. Brain and organ of vision of a Cyclops kitten, at the full period of gestation. Seen from below. (Natural size.) a, organ of vision, single, and of great dimensions ; b, b, cerebral hemispheres seen from below ; d, d, tubercula quadri- gemina ; c, optic nerve, single, and of great size. foetuses consists in the total absence of the organ of smell, in consequence of which de- ficiency the symmetrical organs at either side become united in the middle line and actually engrafted upon each other: the two eyes are conjoined so as to form but a single organ of vision, and the very same metamorphosis occurs in the two orbits, the two optic foramina, the two optic nerves, &c. That this is the rationale can scarcely admit of doubt, since in some parts of the organs the fusion remains incomplete ; thus two crys- talline lenses still exist in the interior of the solitary eye-ball: a double set of muscles with their corresponding nerves are provided for the globe of the eye; and four eye-lids protect the organ in front, causing the aperture of the lids to assume a quadrangular form. General developement of the optic nerves in the higher clauses of animals. Fish.—In fish as a general rule these nerves are highly developed, and exhibit a marked preponderance in size when contrasted with the corresponding nerves in many animals holding a more exalted position upon the scale. This may be explained by the nature of the medium which the fish inhabits; for some of the light incident on the surface of the water is reflected, and another part, after penetrating the water, becomes absorbed, in consequence of the continual disturbance to which the transparency of this fluid is subject; so that fishes necessa- rily require a greater developement of visual apparatus than would suffice land animals for an equal amount of vision. Birds.—In
Size: 1154px × 1734px
Photo credit: © Actep Burstov / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: 1840, 1847, anatomy, archive, book, bookauthor, bookdecade, bookpublisher, booksponsor, booksubject, bookyear, drawing, historical, history, illustration, image, london_sherwood_gilbert_and_piper, mblwhoi_library, page, physiology, picture, print, reference, todd_robert_bentley_1809_1860, vintage, zimmermann_a_albrecht_b_1860, zoology
