. The elements of Embryology,. . jTi A. Head of an Embryo Chick of the Fourth Day viewed from below AS AN OPAQUE OBJECT. (Chromic acid preparation). CH. cerebral hemisptieres. FB. vesicle of tlie third ventricle. Op. eyeball. nf. naso-frontal process. M. cavity of niouth. i*^. M. superior maxillary jirncess of i^. i,the first visceral fold (inferior maxillary process). F. 2, F. 3. second and third visceral folds. A'^. nasal pit. In order to gain the view here given the neck was cut across between the third and fourth visceral iolds. In tlie section e thus made, are seen the alimentary canal al
. The elements of Embryology,. . jTi A. Head of an Embryo Chick of the Fourth Day viewed from below AS AN OPAQUE OBJECT. (Chromic acid preparation). CH. cerebral hemisptieres. FB. vesicle of tlie third ventricle. Op. eyeball. nf. naso-frontal process. M. cavity of niouth. i*^. M. superior maxillary jirncess of i^. i,the first visceral fold (inferior maxillary process). F. 2, F. 3. second and third visceral folds. A'^. nasal pit. In order to gain the view here given the neck was cut across between the third and fourth visceral iolds. In tlie section e thus made, are seen the alimentary canal al with its collapsed walls, the neural canal , the notoehord ch., the dorsal aorta AO., and the vertebral veins F. The incision has been carried just below the upper limit of the pleuroperi- toneal cavity, conspquently a portion of the somatopleure appears at the angle between the two third visceral folds. Almost embraced by the piece of somato- pleure is seen the end of the bidbus arteriosus Ao. In the drawing the nasal groove has been rather exaggerated in its upper part. On the other hand the lower part of the groove where it runs between the superior maxillary proce-^s and the broad naso-frontal process was, in this particular embryo, extiemely shallow and indeed hardly visible. Hence the end of the superior maxillary process seems to join the inner and not, as described in the text, the outer margin of the nasal groove. A few hours later the separation of the two would have been vei-y visible. B. The same seen sideways, to shew the visceral folds. Letters as before. other, and helps to form the inner Avail of each of them. Abutting on the outer side of each groove and so helping to form the outer v^all of each, lie the ends of the superior maxillary processes of the first visceral arch (Fig. 48 B, sm), which like the fronto-nasal process are increasing in size. By their continued growth, the groove is more and more deepened, and leading as it does from the nasal pit
Size: 1658px × 1507px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, bookpublisherlondo, bookyear1874
