176 



AMPHIBIA. 



shaft and rays only on one side. Gills more reduced. Valvular 

 arrangement of conus arteriosus like that in the Batrachians. Lungs 

 paired. 



Fam. Lepidosirenidse. Protopterug ajmectens (fig. 618) Owen, tropical Africa ; 

 Lepidosiren paradoxus Fitzg., Brazil. 



CHAPTER VI. 

 Class II. AMPHIBIA * 



Cold-blooded animals usually with a naked skin, with pulmonary 

 and branchial respiration, and incompletely double circulation. TJie 

 embryos have neither amnion nor allantois. 



The external form of the body is adapted both for an aquatic and 

 a terrestrial life. It presents, however, considerable variations lead- 



FIG. f20. Larva cf Sa'amandra maculata (after Malbranc). M*, median, Ut, lower 



lateral line. 



ing to the creeping, climbing, and jumping land animals. An 

 elongated, cylindrical, or more compressed form is the most frequent, 

 and the body often ends with a large compressed swimming tail. 

 Limbs may be absent, as in the cylindrical Cceciliidce, which live 

 underground in damp earth. In other cases there are only short 

 anterior limbs (Siren), or anterior and posterior stumps, which have 

 a reduced number of toes and are unable to raise the serpentining 

 body from the ground. Even when the extremities have a con- 

 siderable size and end with four or five digits, they act rather as 

 pushing r organs in the movement of the elongated and flexible 

 body. The Batrachians, which have short and stout bodies and are 

 without a tail in the adult state, alone possess powerful limbs adapted 

 for running and jumping, and even for climbing. 



The skin,* which is of great importance not only as a secretory 



* Wagner, " Natiirliches System der Amphibien." M.unich, 1830. 

 Dmneril et Bibron. " Erpetologie generate, etc." Paris, 1834-1854. 



* Fr. E. Schulze, " Epithel-und Driisenzellen. I. Die Oberhaut der Fische 

 and Amphibien." Arch, fur miJtrosk. Anatomie, Tom. III. 



