298 



Marvels of the Universe 



distant days. Ever and again some ' catastrophe, such as a storm blowing them on shore, 

 or a sudden landshde of the chffs, immured these fish, together with giant amphibians and 

 still more gigantic or extraordinary reptiles, in mud. In course of time the mud hardened 

 into natural cement and rock, and was covered in its turn by other la5'ers of deposit ; and 

 thus large portions of Wiirttemberg have become one of Nature's great museums, in which 

 specimens of antique fish, reptile, bird and beast have been locked up for ages away from the 

 discovery of men of science. 



In some cases the ancient clay, hardened into rock, has made such a complete mould of the dead 

 animal, that by filling up this mould with plaster-of-Paris an actual cast has been obtained, showing 

 the shape of the dead creature. This has gone far to help zoologists to determine — with more or 

 less accuracy? — the appearance of some of the Ichthyosaui's when they were alive. 



From these records of the rocks in Wiirttemberg, in England, and in North America, we are able 

 to understand that the Ichthyosaurs were a remarkable order of reptiles developed, far back in the 

 Earth's history at the close of the Primary Epoch, from some very primitive ancestor of all the reptiles, 

 which was at the same time closely related to the preceding frog-like creatures. In the course of 



Bii permission of} [.SVr //. H. Johnston. 



.\ SKELETON OF AN ICH 1 H'l OSAUR. 



The inembers of this race of monsters were first of all frog-like creatures, who afterwards developed into huge water-reptiles, 

 with great back-fins and a vertical tail. Examination of this skeleton will show that the tail end of the spine turned down- 

 wards in order to strengthen the lower lobe 



ages we see tliese Ichthyosaurs growing into huge water-reptiles, with something of the appearance 

 of whales and dolphins. They evolved enormous eyes, protected by plates of bone, with which 

 to scan the waters for their prey. Fins like those of a whale grew out of the back, and the tail 

 developed in course of time two large lobes, which, however, were vertical, instead of horizontal 

 like those in the warm-blooded whales. At first it used to be thought that most of the 

 Ichthyosaurs had died with a broken end to their spine ; but through the investigation of 

 Professor Fraas, of Stuttgart (some of whose photographs are here reproduced), it was shown 

 that the tail-end of the spine turned downwards to strengthen the lower lobe of the tail. It 

 is also evident from these records of the rocks that the Ichthyosaurs did not produce their 

 young in the form of eggs which had tO" be hatched, but developed them inside the body 

 until they could issue forth — three or four in number, perhaps — as living creatures, ready at 

 once to take up the battle of life. 



The fore-limbs of the Ichthyosaurs gradually lost the appearance of five-fingered hands, and 

 became paddles filled with many small bones and covered by a leathery skin and much tissue, while 

 the hind-limbs degenerated into mere flaps on either side of the vent. All the Ichthyosaurs of Europe 

 retained their large number of sharp-pointed, uniform teeth ; but those which attained an extreme 

 development in the shallow seas of North America had, ere the order became extinct, lost their teeth 



