ICHTHYOSAURIA 



121 



simply flattened near its end and not really fin-like. The scapula 

 was longer and less fan-like in shape. 



And all these are remarkable evidences of an increased adapta- 

 tion to water life in the more recent ichthyosaurs over the older 

 ones. Were someone now so fortunate as to find ichthyosaurs in 

 late Permian rocks, we should doubtless have the nearly complete 

 chain between the most highly specialized type of water reptiles 

 and their terrestrial ancestors. 



From the structure of the skeleton alone the early observers 

 were justified in inferring much concerning the shape and habits 

 of the living ichthyosaurs. Later discoveries have added so many 



Fig. 58. — Caudal fin of Ichthyosaurus, after Bauer (left figure); caudal fin of 

 Mixosaurus, after Wiman (right figure). 



definite facts that, at the present time, we know more about their 

 habits than we do of any other extinct reptiles. In various places 

 in England and Germany, especially in Wurtemberg, the remains 

 of ichthyosaurs are found in extraordinary abundance and perfec- 

 tion, not only whole skeletons lying in the positions which they had 

 assumed after the decomposition of their bodies, but also often the 

 actual remains, carbonized, of the skin, muscles, and ligaments, as 

 well as delicate impressions of external parts. Many of these 

 skeletons are obtained from the numerous stone quarries, where 

 they are a sort of " by-product," the sums received for them 

 adding not a little to the income of the quarrymen. So many are 

 obtained in this and other ways that specimens of ichthyosaurs 



