EDENTATA OF THE SANTA CRUZ BEDS. 357 



This doubtful species, which is known only from the type, is the smallest 

 of the genus, though not much inferior to the smaller specimens of 

 N. angulatum. 



MEASUREMENTS. 



Upper dentition, length 037 Lower dentition, length 036 



1, length (*'.., antero-posterior diameter) .0045 T , length 007 



" width (i. e., transverse diameter) . . . .004 " width 004 



^, length 007 j, length 006 



" width 005 5 " width 005 



A, length 007 T > !ength 0075 



" width 007 " width 005 5 



A, length 007 -%, length 013 



" width 005 5 " width 005 



, length 0065 Palate, width at 1 015 



" width 004 " " " 009 



ANALCITHERIUM Ameghino. 



Analcitheritim Amegh. ; Rev. Argent, de Hist. Nat, T. I, 1891, p. 325. 

 Scelidotherium Lydekker, in part ; Anales del Museo de La Plata, T. Ill, 

 1894, p. 92. 



The separation of this genus from Nematherium may prove to be un- 

 necessary, but, for the present at least, seems to be advisable, because of 

 its greater likeness to Scelidotherium, which has led Lydekker to refer it 

 to the latter. The most important distinction from Nematherium consists 

 in the much less decided anterior divergence of the dental series and the 

 parallelism of the sides of the rostrum, while the preorbital region is rela- 

 tively short. 



Assuming the propriety of separating this form generically, it seems 

 probable that it is more particularly related to Scelidotherium, as Nem- 

 atherium is to Mylodon. 



ANALCITHERIUM ANTARCTICUM Ameghino. 



(Plate LXIII, Figs, i, I B .) 



Analcitherium antarcticum Amegh. ; Rev. Argent, de Hist. Nat.. T. I, 



1891, p. 325. 

 Scelidotheriiim antarcticum Lydekker ; Anales del Museo de La Plata 



T. Ill, 1894, p. 92. 



The typical and only known specimen is the skull, lacking the occiput, 

 basis cranii, zygomatic arches, and mandible, of a very young animal, and 



