PREVIOUS TO THE LAST GEOLOGICAL REVOLUTION. Ill 



uroceras, on account of the horny kind of sheath which en- 

 closes the end of its tail. Among the fossil remains of this 

 family, I find traces of a species of an existing genus which, 

 in size, corresponds exactly with the living species ; but as 

 all the species of this genus resemble each other very closely 

 in their internal conformation, 1 dare not yet quite decide up- 

 on the relation between the fossil and the existing species. 



Of the generdi Tolypeutes (Illiger) and Priodon (F. Cuv.) I 

 have hitherto discovered no traces among my fossils. At the 

 same time I find several bones of species of Tatu, of which 

 some resemble the corresponding bones of the genus Eu- 

 phr actus of Wagler, {Dasj/pus, Fr. Cuv., Les Encouherts, G. 

 Cuvier) ; while others agree more with those of the genus 

 Xenurus, Wagler, {Les Cahassous propres Cuv.) ; and others 

 again most resemble those of the proper Dasypus genus. — 

 Without doubt these bones belong to several different species, 

 all of considerable size ; but as I am not yet able to speak of 

 them with certainty, I will leave them for the present, in or- 

 der to pass on to others, of which I possess either more cha- 

 racteristic or more perfect remains. 



Of the first of the two genera I am about to describe, I pos- 

 sess indeed only portions of the dental system ; but they are 

 so characteristic as to be abundantly sufficient, in and by 

 themselves, to indicate the extinct generic forms. The first 

 genus I for the present call Euryodon. And before proceed- 

 ing to describe it I would remark, once for all, that the 

 generic names which I have found myself obliged to apply to 

 animals of whose organization I possess but few remains, are 

 only to be considered as provisional. For although the little 

 that I do possess of them is amply sufficient to determine 

 their independence as a genus, it is yet very possible that the 

 most essential or the most distinctive characters may exist 

 precisely in those parts of the skeleton which I have not yet 

 found. However, it was absolutely necessary to give these 

 new generic forms at least provisional names, for the sake of 

 brevity and clearness in the following general descriptions. 

 The teeth of Euryodon are distinguished from those of all 

 existing armadilloes in this respect, that they are compressed 

 from the front, backwards, while the others are more or less 

 laterally compressed ; for the rest, the grinding surface, as in 



irequents central Brazil and Paraguay ; while the least of all {Das. septem- 

 cinctus, Linn., Das. hyhridus, Desm.), with seven molars, seven belts, and 

 a tail much shorter than the body, occurs only in the extra- tropical part of 

 South America. 



