. Text-book of embryology. Embryology. IX MOLLUSCA 363 completed. The anterior chamber of the eye is formed as an ecto- dermic fold, which arises from the base of the eye-stalk and encloses. it. In this way the outer surface of the adult head is formed and the eye-stalks are no longer prominent. This en- veloping fold we may term the corneal fold. From the spot where the primary eye vesicle closed the rudiment of the outer segment of the lens is formed as an external secretion. The eyelids 'P^' are constituted by a pair of folds similar to those which wall in the anterior chamber, but lying ou
. Text-book of embryology. Embryology. IX MOLLUSCA 363 completed. The anterior chamber of the eye is formed as an ecto- dermic fold, which arises from the base of the eye-stalk and encloses. it. In this way the outer surface of the adult head is formed and the eye-stalks are no longer prominent. This en- veloping fold we may term the corneal fold. From the spot where the primary eye vesicle closed the rudiment of the outer segment of the lens is formed as an external secretion. The eyelids 'P^' are constituted by a pair of folds similar to those which wall in the anterior chamber, but lying out- side the latter. Lying inside the anterior chamber is still another pair of folds which con- stitute the iris. The alimentary canal, which had become a completed tube in the previous period, now shows further develop- ment. The radula sac becomes sharply marked off from the stomodaeum. In front of it two. 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 MacBride, E. W. (Ernest William), 1866-1940; Kerr, John Graham, 1869-; Heape, Walter, 1855-1929. London : Macmillan
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Keywords: ., bookcentury1900, bookdecade1910, bookpubli, booksubjectembryology
