. Biology; the story of living things. . giastrocoelQ teldleciti2al eg"g - toiT'd Diagram showing effect of yolk on the formation of the gastrula. Read text p. 420 and attempt to describe the etfect of yolk on gaslrulation. (After Patten.) In many of the fishes that are relatively large-yolked forms, develop- ment is similar. Young fry of the small-mouthed bass carry around enough yolk to maintain their " flame of life " for about two weeks, after which they begin feedhig on the usually plentiful plankton organisms. Whereas in a macrolecithal type with an abundant supply of yolk
. Biology; the story of living things. . giastrocoelQ teldleciti2al eg"g - toiT'd Diagram showing effect of yolk on the formation of the gastrula. Read text p. 420 and attempt to describe the etfect of yolk on gaslrulation. (After Patten.) In many of the fishes that are relatively large-yolked forms, develop- ment is similar. Young fry of the small-mouthed bass carry around enough yolk to maintain their " flame of life " for about two weeks, after which they begin feedhig on the usually plentiful plankton organisms. Whereas in a macrolecithal type with an abundant supply of yolk, such as a bird's egg, the gut fails to close until a much later date, the embryo literally floating on top of the mass of potential food. Even as development continues there is such a vast quantity of yolk present that it appears impossible for the embryo to complete the ventral body wall until much of the potential food material has been absorbed. As this process takes some time the embryo remains independent of other sources of food material until it gradually depletes the supply, and surrounds the remainder of the yolk with the continued outgrowth of the gradually extending germ 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 Hunter, George W. (George William), 1873-1948; Walter, Herbert Eugene, b. 1867; Hunter, George W. (George William), 1902-. New York, Cincinnati [etc. ] American book company
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