. Evolution and its relation to religious thought . —is free, and some-times carries a claw. In the earliest known and mostreptilian bird, the archasopteryx (Fig. 12), all the three 102 EVIDENCES OF THE TRUTH OF EVOLUTION. fingers are free, have the full number of joints, and allof them carry claws. In the embryo of living birds the fingers are all free, asin the archseoj^teryx. 7. Observe, finally,as an admirable-illus-tration of differentadaptative modifica-tions for the same pur-pose — flight — thestructure of the manusof flying animals. Inthe bat (Fig. 10), theflat flying - plane ismade by
. Evolution and its relation to religious thought . —is free, and some-times carries a claw. In the earliest known and mostreptilian bird, the archasopteryx (Fig. 12), all the three 102 EVIDENCES OF THE TRUTH OF EVOLUTION. fingers are free, have the full number of joints, and allof them carry claws. In the embryo of living birds the fingers are all free, asin the archseoj^teryx. 7. Observe, finally,as an admirable-illus-tration of differentadaptative modifica-tions for the same pur-pose — flight — thestructure of the manusof flying animals. Inthe bat (Fig. 10), theflat flying - plane ismade by enormouselongation of the palm-bones and finger-bones,their wide separationand the stretching ofa thin membrane be-tween them. In thepterosaurs, or extinctflying reptiles (), one finger only isgreatly eularged andelongated, and the flyiug-membrane is stretched betweenit and the hind-leg (Fig. 19), while the other three fingersare free and provided with claws. If it be asked whichfinger is it that is so greatly enlarged in this animal,. PROOFS FROM HOMOLOGIES. 103 we answer, it is the little finger. In birds, on the con-trary, the manus is consolidated to the last decree, toform a strong basis for attachments for the quills whichform the flying-plane, and which are themselves extrememodiflcations of the scales of reptiles. But throughoutall these extreme modifications the same essential struct-ure is detectable. It is perhaps unnecessary to dwell upon the stillgreater modifications of limbs for swimming, as in thewhale (Fig. 16), the ichthyosaur, mosasaur (Fig. 18),and the fish (Fig. 17). A careful inspection of thefigures, after what we have said, will be sufficient toexplain them. In the fish alone the upper segments ofthe limb, viz., shoulder-girdle and humerus, are want-ing, not being yet introduced, and the manus is notyet differentiated into palm-bones and fingers, and thefingers are indefinitely multiplied. All these charactersare indications of low position
Size: 1071px × 2332px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlecontej, bookcentury1800, bookdecade1880, bookyear1888
