76 REPTILIA. 



There are some in which the plicae are almosl effaced; their 

 body is very long and slender, and their muzzle salient. One 

 species is completely blind; the Caec. lumbricoides, Daud. VIII, 

 xcii, 2; it is blackish; two feet in length, and about the thick- 

 ness of a goose-quill. (1) 



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 aflinity 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 

 branchise, and the apparatus 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 branchiie remain, the aorta is divided at 

 its origin into as many branches on each side as there are 

 branchisD. 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 immediately from the veins which form it, that 

 arise most of the arteries which nourish the body, and even 

 those which conduct the blood to be oxygenated in the lungs. 



In those species, however, which lose their branchise, the 

 attendant arteries are obliterated, with the exception of two, 

 which unite in a dorsal artery, giving, each, a small branch 

 to the lungs. It is the circulation of a Fish metamorphosed 

 into that of a Reptile. Batrachians have neither scales nor 



(1) Linnxus mentions it, Mus. Ad. Fred., V, 2, but confounds it with the ten- 

 taculata. 



"We have the skeleton of a Cecilia more than six feet long-, and having- two hun- 

 dred and twenty.five vei-tebrae, but of whose external characters we are ignorant. 



(2) From fixTe^u-xoi (Frog), animals analogous to Frogs. 



