EDENTATA OF THE SANTA CRUZ BEDS. 239 



caniniform ( A ) is of medium size and of the usual compressed oval section ; 

 it is inserted somewhat behind the anterior border of the maxillary and is 

 separated by quite a long diastema from i . The two series of molariform 

 teeth are almost exactly parallel, making the palate of uniform width in 

 this region. These teeth ( A ~ i ) are characterized by their relatively large 

 antero-posterior diameter; in shape they are rectangular with rounded 

 angles ; A is the largest and A the smallest of the series. 

 The preorbital fossae of the maxillaries are unusually deep. 



MEASUREMENTS. 



Upper dentition, length 060 , width OIO 



*-& 035 A, length 006 



Diastema, length 017 " width 009 



1, length (/'. e., antero-posterior diameter) .008 , length 0055 



" width (i. e., transverse diameter) 006 " width 008 



, length 006 Palate, width at preorbital fossae 030 



" width 008 " " "3. 016 



S-, length 008 " " "4 016 



HAPALOPS ROSTRATUS Ameghino. 



(Plate XLIII, Figs, i, i.) 



Xyophorus rostratus Amegh. Enumeracion sistem., etc., 1887, p. 23. 

 f Xyophorus simus Amegh., Ibid., p. 23. 



Although the type of this species is an unsatisfactory fragment of the 

 mandible belonging to a very young animal, the name may be employed 

 for those small representatives of Hapalops, with very short predentary 

 beak of the mandible, which Ameghino has placed in a distinct genus, 

 Xyophorus. The following description is taken from a specimen in the 

 Princeton collection, which consists of an imperfect skull, with mandible, 

 one lumbar, five sacral and four caudal vertebrae, the right os innominatum, 

 part of the right radius and femur and two phalanges of the pes. 



So far as the teeth are concerned, this species hardly differs at all from 

 H. elongatus ; - is of slightly compressed, longitudinally oval cross-section, 

 and is obliquely bevelled by abrasion ; - is quite small and of subquadrate 

 form ; a has a transversely rectangular shape, while - has some tendency 

 to assume a transversely oval shape. In the mandible, T is of quite dif- 

 ferent size and form on the two sides, being noticeably lower and broader 

 on the right side than on the left ; the diastema is very short. The only 

 other tooth preserved is ^, which is of the usual form. 



