THE BATRACHIA OF NORTH AMERICA. 119 



The latest work ou this subject, that of Bouleuger, throws miicli 

 light on it, owing to the opportunities enjoyed by its author for the 

 study of the forms of salamanders found in Asia. He gives the follow- 

 ing table of the genera of the family, but refers them all to the Amblys- 

 tomidas : 



I. Series of palatine teeth converging backwards, forming a V-shaped figure. 



Toes five Jlynohius. 



Toes four SalamandreUa. 



II. Series of palatine teeth nninterrupted, doubly arched, forming a p/^-shaped 

 figure. 



Fingers and toes with epidermic claws Onychodaciylus. 



III. Series of palatine teeth in two arches, convex forwards, separated by a wide 

 interspace. 



Palatine series short, between the choana. Toes live Ranidens. 



Palatine series short, between the choaufo. Toes four Batraehyperiis. 



Of these genera all are Asiatic. The horny claws said to character- 

 ize Onychodactylus may not be confined to that genus or be constant 

 in it, as they develop by the hardening of the epidermis in Amblystoma 

 and some other genera on exposure to dry conditions. 



There are twelve si^ecies of this family lino.wn, distributed as fol- 

 lows: Hynobius 5; Salamendrella 2; Onychodactylus 1; Ranidens 3; 

 Batrachyperus 1. The hyoids of three of these genera have not been 

 examined. 



PLETHODONTID^. 



Gray, Cat. Batr. Grad. Brit. Mus., 1850, 31, exclusive of Amblystoma and Des- 

 mognathus. 



Plethodontidce Cope, J onrn. Ac. Nat. Sci., Phila., 1866, 105. 



Spelerj)inw Cope, Proc. Ac. Nat. Sci. Phila., 1859, 123. 



PlethodontidiV Bolitoglossidce and HemidaetyliidcB Tiallow., Journ. Ac. Nat. Sci., Phila., 



1858, 338, 339. 

 Plethodontince Boulenger, Catal Batr. Grad. Brit. Mus. ed. ii, 1882. 



Yertebrse ami^hicoelous, simple below. Ethmoid wanting; no ptery- 

 goid. 



Carpus and tarsus cartilaginous. 



Vomeropalatine bones not produced posteriorly over parasphenoid ; 

 dentigerous plates on the parasphenoid. 



C/eratohyal undivided, articulating directly with the quadrate bone 

 or cartilatge; no otohyal. One only,- the first epibrancbial in adults; 

 second basibranchial not connected with the first. 



Stapes not connected with the quadrate by cartilage, in adults. 



Vestibule, inner wall osseous. 



The above characters define a very distinct and natural group of 

 genera, which are all but one (Greotriton) confined to America. Many 

 of the species are of small size, some of them indeed of very small 

 size. The largest species, Spelerpes belUi, reaches the dimensions of 

 the Amblystoma tigrimim or Axolotl. Some of the species are hand- 



