AND KANNABATEOMYS AMBLYONYX. 109 



is a simple elongate enamel fold. The lower premolars 

 present a quite diiferent shape , although like the other 

 molars each divided into two separate lobes , for the ante- 

 rior lobe is a very short and simple enamel fold, the pos- 

 terior lobe, however, shows the same enamel folds (one 7- 

 shaped and one simple elongated) like the other lower 

 molars but here united together by a small enamel bridge. 



amblyonyx ^) : the series of molar teeth of opposite sides 

 of the upper jaw very slightly converging, of the lower 

 jaw not converging but each series in the middle very 

 slightly curved. In both jaws the enamel folds are nearly 

 perpendicular to the molar series. Molars not divided 

 into two separate lobes (except the lower premo- 

 lars); the lobes on each tooth of the upper jaw present two 

 very irregular tuning-fork-like folds, united together 

 by a small enamel bridge. The lobes on each tooth 

 (except the premolars) of the lower jaw present an ante- 

 rior V-shaped fold and a posterior elongate one, united 

 together by a small enamel bridge. The lower 

 premolars show about the same shape and folds like 

 those parts in dactylinus , the anterior fold, however, is re- 

 latively and absolutely larger than in that species. 



The difference in the form of the enamel folds of the 

 dentition in the two named species is so great as to com- 

 pel me to form a new genus for the reception oï amblyonyx. 

 This genus I propose to call Kannahateomys^). 



Dactylomys dactylinus and Kannahateomys amblyonyx 

 present moreover in their bony parts as well as in their 

 external characters some differences , as appear to me of 

 more than specific value. So the upper molar series are 

 much more pushed forward in dactylinus, and the nasal 

 bones in that species are more elongate and remember 

 what is to be found in Cavia, Dolichotis , Lagidium and 

 Lagostomus , meanwhile in amblyonyx the named parts 



1) Skull of an adult specimen in the Leyden Museum recently procured 

 from Brazil. 



2) Kxvva, reed , cane and jSxTsai, I mount. 



Notes from the Leyden JVIuseum, Vol. :X11II. " 



