410 COMPAEATIVE ANATOMY. 



a) Ananinia (contintied). 



Derotremata. 



Cryptobranchus, Menopoma, 



Salamanclrina. 



Triton, Salamandra. 

 Anura. 



Pelobates, Bombinator, Hyla, Ceratophrys, Eana, Bufo. 



Gymnophiona. 



Coccilia. 



b) Amniota. 



1) Sauropsida. 



1. Reptilia.* 

 Chelonii. 



Sphargis.Trionyx, Chelonia, Chelys, Chelydia, Emys, Testudo. 

 Saurii. 



Ascalabota. 



Platydactylus, Hemidactylas. 

 Ehynchocephala. 



Sphenodon. 

 Lacertina. 



Iguana, Calotes, Draco, Phrynosoma, Uromastix, Lacerta, 

 Ameiva. 

 Monitores. 



Monitor, Psammosaurus. 

 Scincoidea. 



Scincus, Seps, Anguis. 

 Chalcidea (Ptycliopleura). 



Chalcis, Zonurus. 

 Chamseleonida. 



Chamfeleo. 

 Amphisbfenida (Annulata). 



AmpMsbEena, Lepidostemum. 

 Opbidii.t 



Eurystomata. 



Python, Boa, Coluber, Tropidonotus, Diyophis, Dipsas, Hydro- 

 phis, Crotalus, Trigonocephalus, Vipera, 

 Stenostomata. 



Typhlops, Uropeltis. 

 Crocodilini. 



Alligator, Crocodilus, Eamphostoma. 



2. Aves.t 

 Ratitre. 



Strutliio, Dromteus, Apteryx. 

 Carinatfe. 



GallinaceEe. 



Megopodius, Penelope, Cras, Ciyptums, lagopus, Tetrao, Pavo, 

 Numida, GaUus, Phasianus, 



* The various divisions of this class appear to be the very divergent terminal twigs of 

 a branch of the Vertebrata, which was in former times largely represented. Many of the 

 fossil divisions which are ascribed to the EeptiUa, such as the Enaliosauria, apparently, 

 however, branched off from the Vertebrate phylum before the Amphibia. In another 

 group of fossil Saurii we find forms intermediate between the Eeptilia and Birds ; and 

 that most markedly in the characters of the skeleton of the foot. These are the 

 Ornithoscelida. By uniting Heptiles and Birds into one division of the Sauropsida, 

 as Huxley has done, we put these relations in theu- proper light. 



t The Ophidii form a division nearest to that of the Saurii, and derived from it, and; 

 with it, equivalent to the Chelonii or Crocodilini ; and they were thus put together by 

 Stannius as Streptostylica. 



J The class of Birds which arose from reptilian foi-ms is one which is divided by 

 the most important points in its organisation into groups which diverge very slightly 

 from one another, for the characters of these subdivisions present distinguishing points 

 of very slight importance in comparison with those of the other divisions of the groups 

 of the Vertebrata. Through the Saururi (Archa-opteryx) they are directly connected 

 vrith the Ornithoscelida. 



