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Feles, not possessing the flat projection on the large tearing 

 molar of the upper jaw, which is found in all the other pre- 

 daceous genera, and the development of which is in inverse 

 proportion to the animal's carnivorous propensities. I have 

 recognized this form of dentition in a small animal of the 

 extinct Fauna of this region, which does not exceed the 

 domestic cat in size ; and which, for that reason, I call Cy- 

 nailurus minuta. Besides this, I have discovered the re- 

 mains of two species of the normal feline form ; one as large 

 as the long-tailed tiger-cat [Felis macroura, Pr. Max.), the 

 second, larger than the jaguar, [Felis Onga, Lin.), and 

 comparable to the largest species of the old world, the tiger 

 and the lion. The genus Canis, at present comprises two 

 species in this district ; of which one (Canis Azarce) resem- 

 bles our fox in size, form, and habits ; while the other (the 

 Guara, Canis jubatus), differs more from its congeners. Its 

 extraordinarily high legs, and halting gait, exhibit a resem- 

 blance to the Hgcena, which, however, its timid disposition 

 does not bear out. In like manner, I have found traces of 

 two species of this genus, among my fossil remains. One 

 of them [Canis protalopex), evidently belongs to the sub- 

 group of Vulpes, although the fragments I have as yet ob- 

 tained are not sufficient to determine its exact relation to the 

 living species. The other [Canis troglodytes), belongs to 

 the more carnivorous division of wolves and jackals. The 

 far greater lightness of its extremities distinguishes it well 

 from the Guara, and brings it nearer to the European wolf, 

 from which, however, it differs in its longer and w^eaker neck, 

 a character that again approximates it to the Guara. It was 

 equal to either of them in size, and committed fearful havoc 

 among the antediluvian inhabitants of these regions, whose 

 remains are found amassed together in the caves that served 

 for its den. Scarcely less frightful were the ravages com- 

 mitted by another predatory animal, not much bigger than 

 our fox ; which, in general character, much resembles the 

 jackal division of the genus Canis, but differs from all of that 

 class in the more powerful development of its dental system, 

 and the absence of the hindmost tuberculated molar in the 

 under jaw. Its principal food consisted of the various spe- 

 cies of Paca, to which latter genus belongs that enormous 

 quantity of bones I have described in my account of the 

 cavern of Cerca Grande. For this remarkable animal (which 

 may be considered as a sub-genus of Canis, in like manner 

 as Cynailurus may be regarded a sub-genus of Felis), I pro- 

 pose the name of Speothos, or jackal of the caves; and for 

 the species here described, which is the only one I hitherto 



