. The common frog. Frogs. 82 THE COMMON FROG. [chap. order, which has a skull, the temporal fossa of which is similarly enclosed by bony Fig. 46.—External form of Lopkiomys. This unexpected discovery completely destroys any weight which might be attached to this character as an evidence of genetic affinity. It does so, because it is inconceivable that this Rodent should have directly descended from a common progenitor of frogs and of Chelonians through a line of ancestors which never lost this cranial shield, though the ancestors of all other beasts, all birds, and all reptiles, excep
. The common frog. Frogs. 82 THE COMMON FROG. [chap. order, which has a skull, the temporal fossa of which is similarly enclosed by bony Fig. 46.—External form of Lopkiomys. This unexpected discovery completely destroys any weight which might be attached to this character as an evidence of genetic affinity. It does so, because it is inconceivable that this Rodent should have directly descended from a common progenitor of frogs and of Chelonians through a line of ancestors which never lost this cranial shield, though the ancestors of all other beasts, all birds, and all reptiles, except turtles, did lose it. It is inconceivable, for if it were true, a variety of the lowest mammals (Marsupials ^ and Monotremes^) must have less diverged from the ancient common stock than have the members of the Rodent order, and nevertheless these lowest mammals exhibit no trace whatever of such a cranial shield. Here then we have an undoubted example of the • Opossums, kangaroos, &c. " The Omithorhynchus and 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 Mivart, St. George Jackson, 1827-1900. London, Macmillan and co.
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Keywords: ., bookcentury1800, bookdecade1880, bookpublisherlondo, bookyear1881
