580 PALEONTOLOGY 



at all as yet in America, either North or South. The high degree of 

 fitness for different habits, or radiation, of the anomodonts is dis- 

 tinguished from that of any other reptiles at any time by its numer- 

 ous analogies to the radiation of the mammals, namely, into very 

 large and very small forms, into carnivorous and herbivorous, into 

 terrestrial and possibly into aquatic types; in fact, some of these 

 animals, if seen on land to-day, might readily be mistaken for mam- 

 mals. 



The second offspring of the Cotylosauria, on the contrary, the 

 Diaptosauria, are essentially and unmistakably saurians; that is, if 

 seen about us to-day they would undoubtedly at first be described as 

 lizards. They were still more broadly cosmopolitan in range, being 

 scattered over both Americas (Pelycosauria, Proganosauria) , Europe 

 (Protorosauria, Rhynchosauria), Asia (Rhynchosauria), and Africa 

 (Proganosauria, Rhynchosauria). They are also found highly diversi- 

 fied in type, but all their analogies of fitness are with the reptiles and 

 not with the mammals. It is of prime importance that more of these 

 diaptosaurs be found, and that those already known in the museums 

 should be more critically examined. What we already know, how- 

 ever, enables us to establish the following facts: first, that the par- 

 entage of these animals is more probably among the cotylosaurs than 

 among the anomodonts, and second that already in the Permian 

 they had formed a sufficiently large number of branches to be 

 regarded as a fully evolved radiation. 



Problem of the Adaptation of the Mesozoic Reptiles 



In the Triassic the offspring of the anomodonts and of the diapto- 

 saurs appear as the third generation from the cotylosaurs. 



The recurrent difficulty arises that the actual points of contact or 

 transition from the anomodonts are wanting, and we must continue 

 to reason by the ideal reconstruction of the hypothetical linking 

 forms. Such reasoning connects the Testudinata (turtles and tor- 

 toises), the Sauropterygia, or marine plesiosaurs, and, singularly 

 enough, our own ancestors, the primordial mammals, with the group 

 of anomodonts, and not at all with that of the diaptosaurs. Here in 

 the Upper Permian and Lower Trias we must await both discovery 

 and the closest critical analysis, but if this still hypothetical affiliation 

 be confirmed by discovery, as I personally am sanguine it will be, 

 then it will be true to say that the mammals, and hence man, are 

 much more nearly affiliated to the anomodonts than to either the 

 lizards or snakes, which are both on the great Diaptosaur branch. 

 Our presence on the great anomodont branch and remoteness from 

 the creeping and crawling reptiles will perhaps afford some consola- 

 tion to those who still shrink from the ultimate consequences of 



