. The biology of the amphibia. Amphibians. 94 THE BIOLOGY OF THE AMPHIBIA can impress itself on the germ. Thus, while cold has been shown to induce the European land salamander to retain the young for longer periods in the oviducts even until metamorphosis (Kam- merer, 1907) and this condition is typical of the related Sola- mandra atra (a high mountain species), Lantz (1927) found that the former species, S. salamandra, may sometimes also produce metamorphosed young in nature at a moderate Fig. 32.—The influence of light on the eye of the cave salamander, Typhlo- triton spelaeus.
. The biology of the amphibia. Amphibians. 94 THE BIOLOGY OF THE AMPHIBIA can impress itself on the germ. Thus, while cold has been shown to induce the European land salamander to retain the young for longer periods in the oviducts even until metamorphosis (Kam- merer, 1907) and this condition is typical of the related Sola- mandra atra (a high mountain species), Lantz (1927) found that the former species, S. salamandra, may sometimes also produce metamorphosed young in nature at a moderate Fig. 32.—The influence of light on the eye of the cave salamander, Typhlo- triton spelaeus. A. A blind adult reared in the dark for 203 days after the beginning of metamorphosis. B. Another, reared in the light for approximately the same period, retains and further develops the functional eyes both possessed while larvae. Mutations in other groups of animals have frequently been found to resemble modifications, but there is no experimental evidence that modifications produced during life in the body can be transferred to the germ plasm and become hereditary. Those who believe this possible would postulate long periods of time to accomplish this result. The evidence available is, however, against such an assumption (Cuenot, 1925). Preadaptation.—Instances of preadaptation are given in the discussion of behavior (Chap. XVI) and in the origin of the brood- ing habit (Chap. XVII). The "sucking discs" of tree frogs are. 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 Noble, Gladwyn Kingsley, 1894-1940. New York : McGraw-Hill
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