File:Outlines of comparative physiology touching the structure and development of the races of animals, living and extinct - for the use of schools and colleges (1870) (14596352997).jpg

Identifier: outlinesofcompar00agas (find matches)
Title: Outlines of comparative physiology touching the structure and development of the races of animals, living and extinct : for the use of schools and colleges
Year: 1870 (1870s)
Authors: Agassiz, Louis, 1807-1873 Gould, Augustus A. (Augustus Addison), 1805-1866 Wright, Thomas, 1809-1884
Subjects: Physiology, Comparative Zoology
Publisher: London : Bell & Daldy
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library

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ear in any considerable number, whereas,in the palaeozoic age, there were chiefly marine animals, breathing by gilis,and a few reptiles known only by their foot-marks. D D 2 404 GEOLOGICAL SUCCESSION OF AJSTIMALS. therium, from the resemblance of the impressions to a hand.The mollusca, articulate, and radiata approach those of the fauna of the suc-ceeding period. § 673. TheOolitic fauna isremarkable forthe great numberof gigantic rep-tiles it contains.In this formationwe find thoseenormous amphi-bia, known underthe name Ichthy-osaurus, Plesio-saurus, and Me-galosaurus. Thefirst, in particular,the Ichthyosauri,greatly aboundedon the coasts ofthe continents ofthat period, andtheir skeletons areso well preserved,that we are ena-bled to study eventhe minutest de-tails of their struc-ture, which differsessentially fromthat of the rep-tiles of the pre-sent day. Insome respectsthey form an in-termediate linkbetween fishesand mammals,Fig. 383.—Plesiosaurus rvgosus.—Ovren. and may be con-
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AGES OF NATURE. 405 sidered as the prototypes of the whales, having, like them,limbs in the form of oars. The Plesiosaurus (fig. 383) agrees,in many respects, with the Ichthyosaurus in its structure,but is easily distinguished by its long neck, which somewhatresembles the neck of some aquatic birds. A still more ex-traordinary reptile is the Pterodactylus (fig. 384), with itslong fingers, like those of a bat, for the support of wings, bywhich it was enabled to fly.

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