REPTILIA. 261 



The third and last order of the naked Reptilia or Batrachia is to be 

 found in the Peromeles, embracing but one family, the Cceciliadce. Until 

 within a comparatively recent period the species of this family were 

 included among the Ophidia, on account of their serpentiform body. This, 

 however, while cylindrical, and entirely destitute of limbs, yet has the 

 scales so minute as to be almost entirely concealed* in the folds of the skin. 

 The anus is situated at the extremity of the body, and presents a rounded, 

 plicated orifice, instead of a transverse slit. The most striking batrachian 

 characters, however, are to be found in the double occipital condyle, and 

 the existence of branchiae in the young. The principal difference between 

 the Cceciliadae and the other b.atrachians is to be found in the entire 

 absence of limbs and the presence of true ribs. 



Of the eight known species, distributed in four genera, five are natives 

 of America, two of Asia, and one of Africa. The most conspicuous 

 characters of the genera are to be found in the position of the pits or false 

 nostrils, which in Caecilia are below the true nostrils, in Siphonops one at 

 least before each eye, in Epicrium below the eyes on the lips, and in 

 Rhinatrema are entirely wanting. The third of these genera is peculiar 

 to Asia, the others are all represented by South American species. One 

 species of Siphonops, S. mexicanus, is a native of Mexico. 



Having thus finished the consideration of the living batrachian fauna, it 

 becomes necessary to devote a small space to that of the fossil species. 

 We have already referred to the genus Orthophya, as being probably one 

 of the Proteidae, and to Anurias, as occupying a station intermediate 

 between the living Menopoma and Megalohatrachus. Three species of 

 true Salamandrinae are described as occurring in Central Europe, and 

 referred to the ambiguous genus Triton. Among the oldest indications of 

 air-breathing vertebrates are to be found certain tracks or foot-marks, 

 from the coal measures of Westmoreland county, Pennsylvania. These 

 decidedly salamandrine vestiges indicate an animal far exceeding in size 

 any of its allies of the present day. Somewhat similar foot-prints have 

 been found in various quarries of Central Europe, and ascribed to a hypo- 

 thetical Cheirotherium. It is supposed, by some geologists, that they were 

 made by a Labyrinthodont. Traces, also, of probably batrachian foot- 

 marks are to be found in the new red sandstone of Connecticut and Massa- 

 chusetts. A few of the anourous batrachia have been found fossil in 

 France and Germany, some of them referred to the modern genus Rana. 



Sub-class 2. Reptilia sauAMATA. 



We have already referred to the principal features of this sub-class in 

 treating of Reptilia in general. It only remains for us briefly to state in 

 what it diflfers from the Reptilia nuda, and then proceed to an illustration 

 of the various orders and their subdivisions. This difference consists 

 mainly in the dry horny or bony covering, as distinguished from the moist, 

 naked skin of the Batrachia. Instead of a condyle on each side of the 



ICONOGRAPHIC ENCYCLOPEDIA. — VOL. IL 30 465 



