INTRODUCTORY OBSERVATIONS. 75 



by cellular lungs. Tympanum concealed. Impregnation 

 effected by sexual contact, at least in most instances. 

 Genera. Salamandrina, Salamandra, Molge. 



Order III. AMPHIPNEUSTA. 



Body elongate, formed for swimming. Feet either four or 

 two anterior only. Tail compressed, persistent. Respira- 

 tion aquatic by means of branchiae throughout life, co-exist- 

 ing with rudimentary lungs. Branchiae external, persistent. 

 Eyes with palpebrse. 



Genera. Proteus, Siren, Menobranchus, $c. 



Order IV. ABRANCHIA. 



Body long, formed for swimming. Feet four. Cranium 

 solid. Tail compressed. Respiration by means of lungs 

 only. Branchiae none. No metamorphosis known. 



Genera. Menopoma, Amphiuma, <*c. 



Order V. APODA. 



Body elongate, slender, anguiform. Feet none. Tail 

 very short, almost wanting. Lungs one larger than the 

 other. (The existence of branchiae at any period of life un- 

 known.) Ribs very short. Sternum wanting. Ears con- 

 cealed. Impregnation probably internal. 



Genus. Ccecilia. 



I do not offer this arrangement either as wholly original, 

 nor as absolutely natural ; but it appears to me to be less 

 objectionable than the others which have been proposed. 



It is exclusively to the first and second order that the few 

 Amphibia which are indigenous to this country belong ; and 

 I shall confine my observations on the general characters of 

 the class, and on their physiological peculiarities, to 



