EDENTATA OF THE SANTA CRUZ BEDS. 283 



MEASUREMENTS. 



A, width oio 3 , length 005 



Lower dentition, length 03 1 " width 006 



" j_ f . . .0205 i, length . . .007 



T , length 003 " width 0065 



T , width , 0025 Mandible, depth below 5 019 



j, length 0045 " length condyle to T 068 



" width 0065 



ANALCIMORPHUS GIGANTEUS Ameghino. 



(Plates XLVII-XLIX.) 



Analcimorphus giganteus Amegh. ; Enum. Synopt. des Mamm. Foss. de 

 Patagonie; 1894, p. 165. 



In addition to the type in the Ameghino collection, this species is rep- 

 resented in the Princeton Museum by two individuals, one of which (No. 

 15,163, Plate XLVII) is a fine skull, lacking most of the occiput and the 

 mandible, and the other (No. 15,561, Plates XLVIII, XLIX) consists of 

 the skull, without mandible, four cervical, twelve thoracic, four lumbar 

 and three caudal vertebrae, the sacrum, pelvis, hind-limb and pes almost 

 complete. Both specimens were found by Mr. Peterson near Corriken 

 Aike. At- first sight, the two skulls appear to be quite different in their 

 proportions, so much so that I was inclined to separate them specifically 

 and have, on p. 174, labelled the figure of the pes as A. leptoceplialns, 

 but the difference is at least partially due to the fact that the isolated skull, 

 which was imbedded in a soft matrix, is free from distortion, while the 

 other, which was in a very hard concretion, has been laterally compressed 

 and thus seems to be unduly narrow. 



The most obvious distinction of this species from the preceding one is 

 its very much larger size, but there are additional differences in the teeth. 

 Of the upper series - is the smallest and the portion protruded from the 

 alveolus is very small, both in height and in diameter ; it is of irregularly 

 oval section and recurved ; the grinding surface is inclined ; the tooth is 

 inserted well behind the anterior border of the palate and is followed by 

 a considerable diastema ; - is styliform, of oval or irregularly quadrate 

 section, and has an inclined masticating surface, with high anterior and 

 very low posterior crest, enclosing a rounded, shallow depression ; - and 

 all the succeeding teeth are isolated by considerable interspaces ; 3 -, the 

 largest of the series, is transverse and either oval or pyriform in shape ; 



