III.] CARNIVORA. 71 



migrated from the higher latitudes of the northern hemisphere to 

 find a refuge in these two far distant localities. It may be 

 mentioned that the Solenodontidce and Centetidce, together with the 

 Potamogalida of western, and the Chrysochloridcz, or golden moles, 

 of southern Africa, constitute a section of the order distinguished 

 from all the other forms by having the cusps on their upper molar 

 teeth arranged in the form of the letter V, instead of in that of a 

 W ; and it will not fail to be noticed that the whole group is now 

 exclusively a southern one. Whether it is represented in the Santa 

 Cruz beds is not quite certain, although one lower jaw has been 

 referred to it by Dr Ameghino 1 under the name of Necrolestes. 

 Be this as it may, it is clear that, with the exception of the afore- 

 said shrews, insectivores with W-shaped molars are entirely want- 

 ing in the realm ; and that such V-shaped types as still exist, or 

 formerly occurred, evidently indicate an ancient northern group. 

 Other instances of the survival in South America and Madagascar 

 of allied forms will be noticed in the sequel, and admit of a 

 somewhat similar explanation. 



Although fairly well represented at the present day, the carni- 

 vores of this realm have but few absolutely charac- 



. Carnivora. 



tenstic forms, and as no remains of the true Carni- 

 vora occur in the Santa Cruz beds, the whole of them may be 

 regarded as comparatively late immigrants from the north. The 

 civet family ( Vsvtrrida) and hyaenas (Hyanidcz) are totally wanting 

 at all epochs, as indeed they are throughout the whole of the New 

 World; but the weasel tribe (Mustelidce) have a comparatively 

 small number of representatives. Cats (Felidcz) on the other 

 hand are numerous, although several species, and more especially 

 the puma (Felts concolor), range to a greater or less extent into 

 North America. Such a cosmopolitan genus is, however, of no 

 importance whatever from a distributional point of view; and 

 much the same may be said of the extinct sabre-tooths (Machar- 

 odus), which were distributed in Tertiary times throughout the 

 entire northern hemisphere. Unknown in the deposits of Monte 

 Hermoso and Santa Cruz, this genus is represented by a gigantic 

 species in the Pampean, which undoubtedly reached the country 



t 



1 Bol. Ac. Cordoba, Vol. xm. p. 364 (1894). 



