622 SCIENTIFIC RECORD FOR 1882. 



Shufeldt (R. W.)- Remarks upon the Osteology of Opheosaurua ventralis, Proc. U. 



S. Nat. Mus., V. 4, pp. 392-400. 

 Straucli (A. ). BeiuerkuDgen iiber die Eidechsenfamilie der Amphisbaenideu. Mfilang. 



Biolog., t. 11, pp. 355-479. 



( Ophidians. ) 



Forbes (W. A.). Observations on the Incubation of the Indian Python (Python molu- 

 rus). Report 51 Meet. Brit. Assoc. Adv. Sc, p. 723-724. 



(CJielonians.) 



True (Fred. W.). On the North American Land Tori;oises of the genus Xerobatea, 

 Proc. U. S. Nat. Mus., v. 4, p. 434-449. 



{Dinosaur ians.) 



Marsh (O. C). Principal characters of American Jurassic Dinosaurs. — Part V. Classi- 

 fication of the Dinosauria. Amer. Journal Sc. (3), v. 23, pp. 81-86. 



Reptiles of the American Eocene. 



The Cretaceous was pre-eminently the age of Eeptiles, and with 

 that period died out many strange types of the class. In the Tertiary 

 age the reptiles were developed under the same grand orders as those 

 of the present, but under some peculiar families and many peculiar 

 genera. Those of the Eocene of North America have been reviewed 

 by Professor Cope, and no less than 91 species are recognized, and are 

 segregated under four orders — the Crocodilians with 18 species, the 

 Tortoises with 42, the Lacertilians with 25, and the Ophidians with 6. 

 The ratios between the several types will thus be seen to be very dif- 

 ferent from those exhibited by any existing fauna, but the discrepancy 

 is, doubtless, to some extent due to our imperfect knowledge; never- 

 theless, the real ratios were probably not very different from those al- 

 ready furnished by palaeontology. 



Professor Cope well remarks that " the Eocene reptiles were not a 

 new creation nor a new evolution, but a remnant of the types that had 

 co-existed with the monarchs of life during previous ages. We must 

 except from this statement the serpents, which first appear in numbers 

 at this time, only one Cretaceous species having been found by Dr. 

 Sauvage in France. The crocodiles, tortoises, and lacertilians represent 

 orders already abundant in the Mesozoic faunae. Their decadence in 

 Central North America did not commence until the Miocene period, 

 when the crocodiles and nearly all the tortoises disappeared." 



The Crocodilians, according to Cope, were represented by only 2 

 genera, both of the family Orocodilidae, Crocodilvs, with 16 species, 

 and Flerodon, with 2. " The Eocene species of true crocodiles differ 

 much in size and characters, ranging from the G. heterodon, which is 

 not larger than an Iguana, to the G. antiquus and G. clavis, which rival 

 the existing species of the East Indies." 



The tortoises of the Eocene are of unusual interest. Eight families 



