. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. .k b I i â !£ik- â - Fig. 17. So important relatively is the process of folding that it has apparently- been regarded by some authors as almost the sole developmental pro- cess. How important a r61e it plays is well illustrated in Figure 18, where (excepting the nerve masses and the heart, which are unrepresented) all of the differ- entiated organs of the squid which at this stage lie in the sagittal plane are represented. And these are seen to have arisen by the foldings of the unilaminar blasto
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. .k b I i â !£ik- â - Fig. 17. So important relatively is the process of folding that it has apparently- been regarded by some authors as almost the sole developmental pro- cess. How important a r61e it plays is well illustrated in Figure 18, where (excepting the nerve masses and the heart, which are unrepresented) all of the differ- entiated organs of the squid which at this stage lie in the sagittal plane are represented. And these are seen to have arisen by the foldings of the unilaminar blastoderm which covers the yolk. The connec- tions of the otocyst and the shell-gland with the exterior are now lost, but fin, mantle margins, funnel, and the various appendages of the alimentary tract, as well as the tract itself, are all seen to be arising as foldings of the blastoderm. This view does. aB/ ttVo*?. Fig. 18. Fig. 17. Diagram representing the process of folding as it occurs in proto- plasmic layers. By excessive growth between a and b, the fold a o b is, pro- duced. Fig. 18. Sagittal section of an embryo of Loligo vulgaris, showing the origin of organs through foldings of the blastoderm. From K. & II., Fig. 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 Harvard University. Museum of Comparative Zoology. Cambridge, Mass. : The Museum
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Keywords: ., bookauthorha, bookcentury1800, bookdecade1860, booksubjectzoology
