CHAPTER IX 

 PROGANOSAURIA 



MESOSAURUS 



There is some doubt whether those little creatures of Paleozoic 

 times, to which some years ago the late Professor Baur gave the 

 ordinal name Proganosauria, are really entitled to so much distinc- 

 tion among reptiles. The question of their rank has been much 

 disputed for the past twenty years without any positive conclusion. 

 Nor were they wholly aquatic in habit, though they did possess many 

 aquatic adaptations. That they were skilful and fleet swimmers, 

 and capable of rapid evolutions in the water is quite certain, and, 

 as the oldest known water reptiles, they are of more than passing 

 interest. 



But two genera and three or four species of the group are known, 

 and of them, even, our knowledge in some respects is not as com- 

 plete as one could desire. The first description of any member of 

 the group was by the late Professor Gervais of Paris in 1867. He 

 had only the anterior part of a single skeleton, from the Karoo beds 

 of South Africa, to which he gave the name Mesosaurus, a rather 

 meaningless term signifying "middle" or ''intermediate" saurian. 

 Nothing more was learned about any form till 1885, when the late 

 Professor Cope described a specimen from the supposed Carbonifer- 

 ous of Brazil, which he believed to be closely related to Mesosaurus, 

 though he had only a very imperfect specimen. He called it 

 Stereosternum, also a meaningless term, since none of the animals 

 has a "solid sternum," nor any sternum at all, in fact! A few 

 years later, in 1888 and 1892, the late Professor Seeley of England 

 studied a number of specimens of Mesosaurus, adding not a little 

 to our knowledge of the animals. More recently Dr. Woodward of 

 England and Professor Osborn of America have given us still further 

 information concerning them, and within the past few years Dr. 

 McGregor of Columbia University has figured and described excel- 

 lent specimens of a new species from Brazil, which he calls Meso- 

 saurus brasiliensis. Not only were Dr. McGregor's discoveries of 



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