CREATION BY EVOLUTION
changes with a fair assurance that, one after another, forms showing the comparable actual stages might be found. Here the lack of the connecting links does not seriously disturb the evolutionist, although their discovery would be an event of profound interest.
Our own lineage lies of course in the mammalian line; hence the dawning of mammalian life is of intense personal concern. Here we know much of the truth, for many of the stages have been revealed. The chief distinctions that separate the mammals from their reptilian prototypes are the peculiar methods of nourishing the young both before and after birth, much of the internal mechanism of the mother being directly or indirectly modified as a result of this habit. That the early mammals were egg-layers is attested by the retention of the egg-lying habit in the monotremes, such as the duckbill of Australia, the lowliest of existing mammalian forms, which, with many another evolutionary laggard, is a veritable living fossil, existing in a place remote from the busy competition that impels advance. The palaeontologist cannot trace the development of these diagnostic mammalian characteristics, for they are limited largely to soft parts. The preserved strictly mammalian features that may be compared with features possessed by members of the ancestral reptilian group are few. We find differentiated teeth, which are embedded in the rear of the jaw by more than one root; a single bone in the lower jaw, which is directly articulated with the temporal bone of the skull; and other minor details, largely changes toward greater simplicity.
Back at the beginning of the age of reptiles there existed, mainly in the Southern Hemisphere, a group of reptiles known, from their differentiated dog-like teeth, as cynodonts, from κυνός, a Greek word for dog. That they were not mam-
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