OPHIDIA. 193 



FAMILY III. 

 NUDA. 



Our third and last family of the Ophidians, that of the Naked Ser~ 

 penis, consists of but one very singular genus, which several natu- 

 ralists have thought fit to refer to the Batrachians, although we are 

 ignorant as to the fact of its undergoing any metamorphosis. It 

 is the 



CECILIA, Lin.(l) 



So called because its eyes, excessively small, are nearly hidden beneath the 

 skin, and sometimes are wanting. The skin is smooth, viscous and fur- 

 rowed by annular plaits or wrinkles; it is apparently naked, but on dissec- 

 tion we find in its thickness, perfectly formed though delicate scales, 

 regularly arranged in several transverse rows between the folds of the skin. 



ORDER IV. 

 BATRACHIA.(2) 



The Batrachians have a heart composed of but one auricle and 

 one ventricle. They all have two equal lungs, to which at first are 

 added branchiae, that have some affinity with those of Fishes, and 

 which have cartilaginous arches on each side of the neck attached 

 to the hyoid bone. Most of them lose these branchiae, and the ap- 

 paratus which supports them, when they attain a state of maturity. 

 Three genera only, Siren, Proteus, and Menobranchus, retain them 

 for life. 



As long as these branchia remain, the aorta is divided at its origin 

 into as many branches on each side as there are branchiae. The 

 branchial blood is brought back by veins which unite near the back 

 in one arterial trunk, as in Fishes. It is from this trunk, or imme- 

 diately from the veins which form it, that arise most of the arteries 



(1) Caecilia, from Tt/px4, is & Q Latin name of the Slow-worm (Orvet), 

 which in several parts of Europe is still called blind, although it has very 

 fine eyes. 



(2) From aT/>*fcO{ (Frog), animals analogous to Frogs. 



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