. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates. jf. A B FIG. 201, A.—DIAGRAM SHOWING THE MODE OF FORMATION OF THE PRIMARY OPTIC VESICLES (AR1). VH, fore-brain ; V,V, ventricular cavity of the brain, which communicates with the cavities of the primary optic vesicles at tt- B.—SEMIDIAORAMMATIC FIGURE OF THE SECONDARY OPTIC VESICLE, AND OF THE LENS BECOMING SEPARATED OFF FROM THE ECTODERM. C, vitreous chamber of the eye, between the lens and retina, which later becomes filled by the vitreous humour ; H, remains of the cavity of the primary optic vesicle ; IB, inner layer
. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates. jf. A B FIG. 201, A.—DIAGRAM SHOWING THE MODE OF FORMATION OF THE PRIMARY OPTIC VESICLES (AR1). VH, fore-brain ; V,V, ventricular cavity of the brain, which communicates with the cavities of the primary optic vesicles at tt- B.—SEMIDIAORAMMATIC FIGURE OF THE SECONDARY OPTIC VESICLE, AND OF THE LENS BECOMING SEPARATED OFF FROM THE ECTODERM. C, vitreous chamber of the eye, between the lens and retina, which later becomes filled by the vitreous humour ; H, remains of the cavity of the primary optic vesicle ; IB, inner layer of the secondary optic vesicle, from which the retina arises ; t, point at which the latter is continuous with the outer layer (AB), from which the pigment epithelium is formed ; L, lens, which arises as a cup-shaped involution of the ectoderm (E) ; *, point of involution of ectoderm to form the lens ; MM, mesoderrnic tissue, winch at J/1, M1, grows in between the outer ectoderm and the lens as the latter becomes separated off, and which gives rise to the cornea as well as to the iris this condition of things is gradually carried still further in Reptiles, until finally the fibres of the two nerves intercross in a very com- plicated manner (c, D), giving rise to a sort of basket-work ; this is finest and most delicate in Mammals, where its structure can only be analysed by comparing a series of sections. To return to the further development of the eye, the ectodermic thickening mentioned above becomes separated from the ectoderm, sinks more and more into the interior of the optic vesicle, and is differentiated to form the crystalline lens (Fig. 201, B). It is usually. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Wiedersheim, Robert, 1848-1923; Parker, W. N. (William Newton), d. 1923. London, Macmillan
Size: 1479px × 1690px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectanatomycomparative
