620 Original Articles. [Oct., 



types, seem to indicate that these vast forests must have existed in a 

 state not very different from their present condition during a vast 

 period. The most northern locality hitherto recorded for any 

 member of this group is Costa Rica, whence Dr. Peters has lately 

 received several examples of a new and very interesting species of 

 the two-toed genus Cholcepus* Thence they extend southwards over, 

 the great wood region of Brazil and Peru to the frontiers of Paraguay 

 and La Plata. About six species of Bradypus and two of the genus 

 Cholcepus have been recognized by naturalists, but several of the 

 former require further elucidation. 



The Entomophagous Edentates of America consist of two very 

 distinct families, the Armadillos (Dasypodidae) and the Anteaters 

 (Myrmecophagidae). The former is rather a numerous group, 

 some twenty species being known to science. A single Armadillo 

 (Dasypus peba var. mexicana, Peters) occurs as far north as Texas. 

 Hence descending southwards, the form is diffused all over the 

 Continent down to Patagonia. In the Argentine Republic Dr. 

 Burmeister records the presence of five species. The more typical 

 section of this family (Dasypodinas) is divisible into several genera. 

 A second sub-family (Chlamydophorinae) contains only the very 

 remarkable form Chlamydophorus, of which the species originally 

 described, and long considered as the only existing representative of 

 this most extraordinary form, is exclusively confined to the vicinity 

 of Mendoza in the Argentine Eepublic. A second species recently 

 described by Dr. Burmeister (0. retusus) is from the province of 

 S te Cruz de la Sierra, in Bolivia. The Anteaters (Myrmecophagidae), 

 very distinguishable from the Armadillos by their extensile tongue, 

 wholly toothless jaws, and hairy covering, are not so numerous in 

 species. Of the largest and only terrestrial form Myrmecophaga, one 

 species only is known to exist. Of each of the two arboreal genera 

 with prehensile tails (Tamandua and Cyclothurus) two species have 

 been described. Both these forms extend to the north of the 

 Panamanic Isthmus, the former into Southern Mexico, f and the latter 

 as far as Costa Rica, whence a second species has recently been 

 described by Dr. Gray 4 



A few words more only remain to be said about the lowest form 

 of the Mammal-type in South America, the Marsupials, which the 

 New World possesses in common with Australia. But whereas in 

 Australia Marsupialism is the prevalent form of Mammalian life, and 

 exhibits itself in several very distinct families, only one. group of 

 Marsupials exists in the New World to which it is likewise peculiar. 

 This is the family of Opossums (Didelphyidae), containing three 

 principal genera (Didelphys, Chironectes, and Myracodon). The first 

 of these contains a series of species of arboreal habits, varying in 

 size from the bulk of a common cat, such as the Virginian Opossum 

 (D. virginiana), to that of a common house-mouse, such as D. tristriata. 

 They are diffused all over Southern and Central America, from the 



* Ch. hoffmanni, Peters, 

 t Cf. de Saussure, ' Rev. Zool.,' 1860. 

 » % C. dorsalis, Gray, * Proc. Zool. Soc.,' 1865, p. 385, pi. xviii. 



