Dr. Rcngger's Mammalia of Paraguay. 471 



anterior feet one pair, and on those of the posterior two pairs, of col- 

 lateral, hard, elevated calli, which give name to the species. The Mus 

 ongitarsus, on the other hand, might at first sight be confounded with the 

 Mus Musculus; but it differs in having the bristles that surround the 

 mouth longer, that is to say, measuring nearly an inch in length; in the 

 length of its tail compared to that of its body being as 1*22 to 1, 

 while in the latter it is only as 108; and in the hinder feet being 

 much longer, their whole length being 14 lines, of which the tarsi 

 constitute 9. The Old Continent pests with which these two species are 

 compared have also found their v^'ay to Paraguay, having been intro- 

 duced by Spanish vessels ; they are now completely naturalized and 

 extend their depredations to the plantations as well as the houses, but 

 do not go far beyond the settlements of man, as the authour never met 

 with them in unfrequented districts, or the isolated dwellings of the in- 

 terior. Two species of Echimys are enumerated, viz. 40. Ech. spi- 

 no5MS, Desm., and 41. Ech. longicaudatus, Rengg. The latter, a single 

 individual of which was taken in the northern part of the country, differs 

 but little from the preceding species, except in the length of its tail, 

 which exceeds that of the body, w^hile in Ech. spinosus it scarcely mea- 

 sures half as much. The variation in colour between the two is by no 

 means striking. There is little that requires particular notice in the 

 remaining Rodentia ; they consist of 42. Myopotamus BonariensiSf 

 Comm., (Quiniija); 43. Sphingurus spinosus, F. Cuv., {Cuiij) ; A4.Lepus 

 Bras'diensis, L., [Tapiti) ; 45. Calogenus Paca, (but one species, the 

 Pay) ; 46. Chloromys .^cuti, F. Cuv,, [Acuti) ; 47. Hydrocharus 

 Cup'jhara, Erxl., [Capiygua) ; and 48. Cavia Aperea, Gmel. With 

 respect to the latter Dr. Rengger maintains that it is specifically distinct 

 from the domesticated Guinea-pig, and gives many excellent reasons 

 for his opinion, taken from important differences in structure, economy, 

 and habits — differences so remarkable that it is difficult to believe that they 

 could have arisen solely from domestication in a distant country. 



The Edentata consist of five species of Armadillo, and two Ant- 

 eaters, as follows: 49. Dasypus 6'Cinctus, L., [Talu-poyii) ; 50. Das. 

 gymnurus, lUig., [Talu-oy]; 51, Das. 9-cinctiis, L., [Tatu-hn) ; 52. 



