(382) A. Kowalevsky. “Weitere Studien üb. d. Entwicklung d. einfachen Ascidien.” Archiv f. mikr. Anat., Vol. VII. 1871.
(383) C. Kupffer. “Zur Entwicklung d. einfachen Ascidien.” Archiv f. mikr. Anat., Vol. VII. 1872.
[182] O. and R. Hertwig. Das Nervensystem u. Sinnesorgane d. Medusen. Leipzig, 1878.
[183] Vide Hensen, Zeit. f. wiss. Zool. Bd. XV.
[184] “Devel. of Cephalopoda.” Q. J. Micro. Scien. 1875, p. 44.
[185] Ueber Sehorgane von Typus d. Wirbelthieraugen, etc., Wiesbaden, 1877, and Archiv f. mikr. Anat. Vol. XIV. pp. 118-122.
[186] Vide Hensen (No. [364]) and S. J. Hickson, “The Eye of Pecten,” Quart. J. of Micr. Science, Vol. XX. 1880.
[187] O. Hertwig. “Die Chætognathen.” Jenaische Zeitschrift, Vol. XIV. 1880.
[188] The eye of Peripatus is similar neither to the eye of the Arthropoda, nor to that of the Chætopoda, but resembles much more closely the Molluscan eye. The hypodermis and cuticle form together a highly convex cornea, within which is a large optic chamber, the posterior wall of which is formed by the retina. The optic chamber would appear to contain a structureless lens, but it is possible that what I regard as a lens may, on fuller investigation, turn out to be only a coagulum.
[189] There would appear to be some confusion as to the nomenclature of these parts in Bobretzky’s account.
[190] It appears to me possible that Lieberkühn may be right in stating that the epithelium of Descemet’s membrane grows in between the lens and the epiblast before the formation of the cornea proper, and that Kessler’s account, given above, may on this point require correction. From the structure of the eye in the Ammocœte it seems probable that Descemet’s membrane is continuous with the choroid.