. Biological lectures delivered at the Marine Biological Laboratory of Wood's Holl [sic]. Biology. THE PRIMARY SEGMENTATION. 131 that the extreme anterior end of the vertebrate brain still bears the marks of primitive segmentation. This, as Dr. Whitman has shown, is also the case with the invertebrates. In Fig. 6, the auditory vesicle is formed. The neural seg- ments of the fore- and mid-brains are no longer discernible ottb. Fig. 6. — Head of embryo after the formation of the auditory vesicle, the first five head segments no longer distinguishable, an, auditory vesicle, na, nasal epithelium,
. Biological lectures delivered at the Marine Biological Laboratory of Wood's Holl [sic]. Biology. THE PRIMARY SEGMENTATION. 131 that the extreme anterior end of the vertebrate brain still bears the marks of primitive segmentation. This, as Dr. Whitman has shown, is also the case with the invertebrates. In Fig. 6, the auditory vesicle is formed. The neural seg- ments of the fore- and mid-brains are no longer discernible ottb. Fig. 6. — Head of embryo after the formation of the auditory vesicle, the first five head segments no longer distinguishable, an, auditory vesicle, na, nasal epithelium, mb, mid-brain. from surface view, but those of the hind-brain, beginning with No. 6, are clearly seen. The neuromeres of that region are now in contact in the median plane ; soon, by the lateral growth of the upper brain wall, they become separated as shown in Fig. 7. This is the stage in which neural segments have been here- tofore described. They have been designated neuromeres. The 1 f<^- .8 a :'". 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 Marine Biological Laboratory (Woods Hole, Mass. ). Boston, Ginn & Co
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbiology, bookyear1895
