Outlines of comparative physiology touching the structure and development of the races of animals, living and extinct : for the use of schools and colleges . In the vicinity of the chorda dorsalis, outwardly, between it and thevertebral laminae, arise thefirst cartilaginous rudiments ofthe bodies of the vertebrae,which blend superiorly withthe laminae of the vertebralarches, close in the canal ofthe spinal cord below, andsurround the cartilaginous co-lumn (sheath) of the chordadorsalis. Towards the fifthday the chorda dorsalis beginsto disappear ; the spinal cord ,. is laterally compressed, an
Outlines of comparative physiology touching the structure and development of the races of animals, living and extinct : for the use of schools and colleges . In the vicinity of the chorda dorsalis, outwardly, between it and thevertebral laminae, arise thefirst cartilaginous rudiments ofthe bodies of the vertebrae,which blend superiorly withthe laminae of the vertebralarches, close in the canal ofthe spinal cord below, andsurround the cartilaginous co-lumn (sheath) of the chordadorsalis. Towards the fifthday the chorda dorsalis beginsto disappear ; the spinal cord ,. is laterally compressed, and Fig. 340. — Anterior end of an „ , f , embrvo somewhat more highly mag- (L. falls into two halves, each of nified, and a few hours older thanthat of fig. 339. a, a, Cranial in- which is again divided intoan upper and an under fas- volucrum ; b, b, vertebral laminae ciculus. It is on the fifth daynear the crests of the now closed ^ t ^ mdimentary eiilarge-dorsal lammse; c, spinal cord pass- . ,. 9ing into the medulla oblongata, d, ments or processes, indicativewhich in its turn passes by a de- of the position of the future ex-pression (the fourth ventricle) into tremities, make their appear-the corpora quadrigemina, e ; /, ance . the earliest traces of themesocephalon (thalami and crura cerebral envelopes were alreadycerebn): a, hemispheres; n, supe- - . _ , ,rior maxillary bone ; i, auditory conspicuous on the fourth ; k, branchial arches; I, The medulla oblongata ( cordis; m, the heart hang- 340, between c and d) is ex-ing forwards; n, bulb of the aorta, tremely flat above, in conse-quence of the divergence of the superior fasciculi from
Size: 1385px × 1804px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, booksubjectzoology, bookyear1870
