50 ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 



This curious little species has been described by Weigman under the 

 present name, — by Tschudi under the generic name of Chaunus, and fully by 

 Bibron, who retained the name originally given to it by Weigman. It now 

 remains only to correct, from Mr. Darwin's notes, some points respecting the 

 colours, which had been mis-stated in consequence of the action of the spirit in 

 which the specimen had been preserved. The colour of this curious miniature 

 representation of a Toad, is "ink black," excepting the palms and soles of the 

 feet, a large transverse spot across the posterior part of the abdomen, two smaller 

 ones near the middle, and in some specimens a few scattered little spots, all of 

 the most intense vermilion red. There is one specimen from Bahia Blanca which 

 has also some small " buff-orange" spots on the upper part.* Mr. Darwin ob- 

 serves that " the appearance of the vermilion colour is as if the animal had 

 crawled over a newly painted board ;" and he adds — " This Toad inhabits the 

 most dry and sandy plains of Bahia Blanca, where there is no appearance of 

 water ever lodging." The other specimens were taken at Maldonado, where 

 it inhabits the sand-dunes near the coast. Mr. Darwin threw one into a pool of 

 fresh-water, but he found it could hardly swim, and he thinks, if unassisted, it 

 would have been soon drowned. 



This species is diurnal in its habits, and may be daily seen under a scorching 

 sun, crawling over the parched and loose sand. M. D'Orbigny brought specimens 

 from Monte Video. 



DIMENSIONS. 



In. Lin. 



Length of the head and body 1 



of the anterior extremities 5 



of the posterior extremities 8 



Genus— UPERODON. Bibr. 

 Uperodon ornatum. Mihi. 



Plate XX.— Fig. 6. 

 Capite multd latiore quam longiore. Dorso olivaceo, maculisfuscis, alho marginatis. 



Habitat Buenos Ayres. 



Description. — Head more than half as broad again as it is long, and equal in breadth to half the 

 entire length of the head and body. Muzzle rounded. Nostrils oval, opening upwards and a 



* This specimen from Bahia Blanca has a much smoother skin than the others ; but from its similarity in all 

 other characters there can be no doubt of its specific identity with them. 



