amphibia; 



Metamorphosis after birth; respiration branchial in young, pulnwnary 

 or pulmonary and branchial in the adidt, but always feeble in the 

 lungs, while active from the skin; lungs with few and coarse cells; blood 

 cold; corpuscles oval, nucleated; circulation incomplete; heart in adult 

 vnth two auricles and a ventricle f ; reproduction oviparous or ovovi- 

 parous ; fcetus anamniate ; allantois wanting, unless the urinary bladder 

 represents it J; skin usually naked or unarmed; skeleton incomplete, 

 internal; cranium with two occipital condyles; nasal sacs and pharynx 

 connected; nervous system cerebrospinal; brain small; cerebellum 

 scarcely visible ; excrementitious and reproductive organs opening into 

 a cloaca. 



The living forms are divided into three orders, as follows : 



Feet present, at least in front ; body not vermiform, a. 



Feet wanting ; body vermiform ; extralimital Omomorpha. 



a. Adult tailless ; body short and thick Anotjka. 



a. Tail always present ; body laoertiloid Ukodela. 



ORDER ANOURA. TAILLESS AMPHIBIANS. 



Metamorphosis complete ; young fish-like, herbivorous, with a long intestinal canal ; 

 gills external at first ; teeth and limbs wanting ; adult without branchial arches ; body 

 short, depressed, raniform, tailless; feet four, posterior longer; tongue large, fleshy, 

 free posteriorly, and capable of protrusion ; ear provided with an eustachian tube ; fenestra 

 rotunda present ; nasal sacs and pharynx connected ; hyoid bone with but one pair of 

 cornua; radius and ulna anchylosed as are also the tib'a and fibula ; astragalus and cal- 

 caneum replaced by two elongated, cjlindrical bones; vertebrae ten, without any dis- 

 tinct atlas ; ureters opening into the oviducts ; fecundation after exclusion of the eggs. 



* For the anatomy of these animals, see Brown's Klassen und Ordnung des Thier- 

 Eeiches, and Dnges' Eecherches sur I'Osteologie et la Myologie des Batraciens a leurs 

 differens Ages. 



t A question has been raised in regard to the structure of the heart in the Perenni- 

 branchiata. Proteus, and also the Axolotl in all probablity have only a single auricle. 



tProf. Wyman, Proc. Boston Soo. Nat, Hist,, p. 58, states from his observations that 

 he considers the urinary bladder of frogs to structurally resemble that of fishes and 

 scaly reptiles. From its anatomical relations to the intestine and vascular system he 

 tegards it as a rudimentary allantois. 



