40 ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 



panum not very conspicuous ; there is a trace of a parotid gland on each side of the neck. The 

 body is rather thick, and the limbs proportionally short. The hinder toes are only connected 

 at the base by a rudimentary membrane, the first four gradually increasing in length, and 

 placed along the side of the matatarsus, one beyond the other ; the fifth on the same line as 

 the fourth, but not more than half its length. The metatarsal tubercle is rather prominent, 

 and there are small subarticular tubercles on the toes of all the feet. 

 Colour. — The colour of the upper parts is brownish black. On each side near the thigh are three 

 or four perfectly round black spots, each surrounded with a white line. The under parts 

 whitish. 



Of this second species of a rare and remarkable genus, one specimen only 

 exists in Mr. Darwin's collection. It is only the third known instance, in the 

 family of the Ranid^:, of the absence of palatine teeth ; the others being 

 Oxyglossus Lima of Tschudi, and Leiuperus marmoratus of Bibron. The present 

 genus must be considered as nearly approaching the family of the BufonidjE in 

 the absence of palatine and the extreme minuteness of the maxillary teeth, in 

 the extremely small gape of the mouth, the thick form of the body, the shortness 

 of the limbs, and the existence of rudimentary parotid glands. I have not had 

 an opportunity of comparing this specimen with those on which Bibron founded 

 the genus, but I cannot doubt the specific distinction between them. 



DIMENSIONS. 



In. Lin. 



Length of the head and body 9 



of the anterior extremities 5 



of the posterior extremities 1 1 



It was found by Mr. Darwin at Port Desire, and its habitat is very remark- 

 able. " It is bred in and inhabits water far too salt to drink." 



Genus— PYXICEPHALUS. Bibr. 



Pyxicephalus Americanus. Bibr. 



Plate XVIIL— Fig. 2. 



Lingua cordiformi; dentibus palatinis in lined transversa interrupts, inter nares 

 posieriores positis ; tympano celato ; dorso mammillato. 



This curious species has, I believe, only once before been found. A single 

 specimen exists in the French Museum, which was brought from Buenos Ay res 



