. Text-book of embryology. Embryology. 542 EMBEYOLOGY OF THE LOWEE VEETEBBATES oh. distinctly thickened as compared with the outer or pigment layer, and with a narrow optic stalk passing to the thalameneephalon near its floor. In the mouth of the optic cup is the lens but this is seen better a few sections farther on in the series. Turning to the other half of the section it is seen that it is no longer connected with the extra- embryonic somatopleure: in other words the series of sections has now passed the hinder limit of the headfold of the somato- pleure. The pharynx passes out as a pocket
. Text-book of embryology. Embryology. 542 EMBEYOLOGY OF THE LOWEE VEETEBBATES oh. distinctly thickened as compared with the outer or pigment layer, and with a narrow optic stalk passing to the thalameneephalon near its floor. In the mouth of the optic cup is the lens but this is seen better a few sections farther on in the series. Turning to the other half of the section it is seen that it is no longer connected with the extra- embryonic somatopleure: in other words the series of sections has now passed the hinder limit of the headfold of the somato- pleure. The pharynx passes out as a pocket on each side towards the ectoderm—the rudiments of the first pair of visceral clefts (). The neural tube has become greatly increased in size forming the hind brain with its widely expanded cavity—the fourth ventricle. On each side is a large thick-walled sac—the otocyst. Examination of. Fig. 237p.—Transverse section passing through the rudiments of the eye and otocyst. , anterior cardinal vein ; , hind brain ; N, notochord ; opt, optic cup; ot, otocyst; p7i, pharynx; , lirst visceral cleft; , ventral carotid. thai pm. 9<zng. ^h. 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 MacBride, E. W. (Ernest William), 1866-1940; Kerr, John Graham, 1869-; Heape, Walter, 1855-1929. London : Macmillan
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Keywords: ., bookcentury1900, bookdecade1910, bookpubli, booksubjectembryology
