. Biological lectures delivered at the Marine Biological Laboratory of Wood's Holl [sic]. Biology. THE EAR OF MAN. 201 into its anterior and posterior halves, which, owing to the distortion produced by the enormous growth of the Fig. 6. — The left internal ear of a human embryo, 22 mm. in length, seen from without and below. Figure after W. His., Jr. The figure is from a model constructed from serial sec- tions, and represents the ear much magnified. a Anterior canal. am Ampulla. am' Amae. The middle reference line is superfluous. Cochlea. Ductus endolymphaticus. External canal. Sacculus in th
. Biological lectures delivered at the Marine Biological Laboratory of Wood's Holl [sic]. Biology. THE EAR OF MAN. 201 into its anterior and posterior halves, which, owing to the distortion produced by the enormous growth of the Fig. 6. — The left internal ear of a human embryo, 22 mm. in length, seen from without and below. Figure after W. His., Jr. The figure is from a model constructed from serial sec- tions, and represents the ear much magnified. a Anterior canal. am Ampulla. am' Amae. The middle reference line is superfluous. Cochlea. Ductus endolymphaticus. External canal. Sacculus in the restricted sense; really only the recessus sacculi. Utriculus. c d h s u. cochlea, now appear as superior and inferior portions of the canal system of the ear. The development of the special sense-organs of the lateral line in A^nm or the ganoid Dog-fish, as made known by Allis, gives us the key to the solution of the problem of the homologies of the parts of the internal ear. In this fish the inclosure of the canals and the formation of the pores and tubes, while it is undoubtedly the primitive process, is essentially a simple and regular process, and when it is fully carried out t/ie canals arise in separate sections^ each of which contains a single sense- organ. In the young Dog-fish, in which the canals have not begun their development, the sense-organs lie below the surface and may be traced as more or less continuous whitish lines. "These lines mark general and exten- sive surface ; From the bottom of these. 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, bookyear1890
