ANOMODONTIA 103 



geologists and naturalists, because of their intimate relationships to 

 the mammals — so intimate, indeed, that they seem almost to bridge 

 over the interval between the two classes. From higher Karoo 

 beds primitive representatives of the more crocodilian types have 

 been discovered, forms which seem to be the beginning of that 

 order described on later pages as the Parasuchia. 



It would lead us too far astray to mention even, let alone 

 describe, the many forms of reptiles that have been discovered 

 in the Karoo beds; nor indeed is it possible for anyone who 

 has not attentively studied their remains to get a very clear con- 

 ception of many of them, so incompletely have they been made 

 known. 



Doubtless from among all these diverse forms there have been 

 not a few which sought wider opportunities in the water, but, if so, 

 we have as yet very little knowledge of them. One form only, so far 

 as the writer is aware, has been credited with aquatic habits, a 

 remarkable reptile belonging to the group originally called by 

 Sir Richard Owen, the Anomodontia, a word meaning "lawless 

 teeth," and to the genus Lystrosaurus, also described by the same 

 noted paleontologist. A restoration of the skeleton of Lystro- 

 saurus has recently been published by Watson. This restoration 

 the writer has reproduced in the present pages, though he has 

 taken the liberty of making some minor changes, to accord better 

 with what he believes must have been the position of the shoulder- 

 blades and the hind legs. And he would also suggest that the tail 

 in life did not turn down so much at its extremity as depicted by 

 Watson. 



Both Broom and Watson believe that this animal was a power- 

 ful swimmer, and thoroughly aquatic in habit. To the present 

 writer, however, this does not seem so evident. He is rather 

 inclined to believe that the creature was chiefly terrestrial in habit, 

 living probably in marshy regions, and perhaps seeking its food 

 in shallow waters and in the mud. Aside from the position of the 

 nostrils, which it will be observed are rather close to the eyes, 

 a position so characteristic of many swimming reptiles and mam- 

 mals, there is but little indication of aquatic adaptations elsewhere 

 in the skeleton. 



