. The elements of embryology. Embryology; Embryology. 156 THE THIRD DAY. [CHAP. After it has become free, it forms a solid cord, the lower end of which unites with the wall of the nasal cavity. The cord so formed gives rise directly to the whole of the duct proper and to the lower branch of the collecting tube. The upper branch of the collecting tube is formed as an outgrowth from it. A lumen begins to be formed in it on the twelfth day of incubation, and first appears at the nasal end. It arises as a space amongst the cells of the cord, but is not due to an absorption of the central cells i.
. The elements of embryology. Embryology; Embryology. 156 THE THIRD DAY. [CHAP. After it has become free, it forms a solid cord, the lower end of which unites with the wall of the nasal cavity. The cord so formed gives rise directly to the whole of the duct proper and to the lower branch of the collecting tube. The upper branch of the collecting tube is formed as an outgrowth from it. A lumen begins to be formed in it on the twelfth day of incubation, and first appears at the nasal end. It arises as a space amongst the cells of the cord, but is not due to an absorption of the central cells i. Organ of hearing. During the second day the ear first made its appearance on either side of the hind- brain as an involution of the external epiblast, thrust down into the mass of mesoblast rapidly developing between the epiblast of the skin and that of the neural Fig. 53. It>C\ Th Section through the Head of an Elasmobranch Embryo, AT THE Level op the Auditory Involution. au-p. auditory pit; aun. ganglion of auditory nerve ; roof of fourth ventricle ; anterior cardinal vein ; aa. aorta ; ^ G. Born: "Die Nasenhohlen u. Thranennasengang d. amnioten Wirbelthiere, i. Lacertilia ii. ; Morphologisches Jahrbuch, Vol. v., 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 Foster, M. (Michael), Sir, 1836-1907; Balfour, Francis M. (Francis Maitland), 1851-1882; Sedgwick, Adam, 1854-1913; Heape, Walter, 1855-1929. London : Macmillan and Co.
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Keywords: ., bookcentury1800, bookdecade1, booksubjectembryology, bookyear1883
