EDENTATA OF THE SANTA CRUZ BEDS. 59 



the plate, with only a very narrow raised border on the outer side of each 

 bounding groove ; anteriorly, on each side of the neck of the flask, is a 

 nearly square, flat figure. Backward from the neck of the flask passes a 

 faintly marked ridge, tapering posteriorly and ending in a point some dis- 

 tance in advance of the hinder border of the plate. In the anterior median 

 part of the carapace the flask-figure is not distinct and the conspicuous, 

 piliferous pits (already described in P. robustus] are present, but in the 

 posterior region of the movable bands this pattern occurs across the entire 

 width of the carapace. On the sides, where the plates become curved, the 

 flask-shaped figure is somewhat distorted and has an elongate neck. 



In the fixed plates of the pelvic buckler, the flask is less distinct, while 

 the small anterior figure on each side of the neck is divided into two and 

 in some instances the neck itself is severed by a transverse groove, mak- 

 ing five small, anterior figures. 



The upper teeth (Plate XII, figs. 2, 6) of each side form an almost 

 continuous series and the space between - and - is very short, hardly 

 longer than that between - and - ; - is very small and implanted entirely 

 in the premaxillary, as in Dasypiis : - is considerably larger than - and ^ 

 still larger and faintly grooved on the inner side, - is symmetrical, with 

 opposite vertical grooves, while - to ^ inclusive are pyriform, with the 

 smaller end turned obliquely forward and inward : - is the largest of the 

 upper series and behind this the teeth diminish in size to -, which is oval. 

 In the mandible (Plate XII, fig. 5) the first four teeth are small and 

 laterally compressed, though increasing successively in size and thickness, 

 while r is much larger. The five posterior teeth have the usual rudely 

 triangular shape, with rounded angles. The lower dentition slightly 

 exceeds the upper in length. 



The skull (Plate XII, figs. 1-4) is somewhat smaller than that of P. 

 robustus, but of very similar form. The occiput has a prominence for the 

 vermis of the cerebellum, but no nuchal ridge, and the median dorsal 

 fossa is much narrower and shallower than in the last-named species, 

 while the sagittal crest and area are less prominent. The rostrum is long 

 and tubular, but slightly expanded and spatulate at the tip, which is a 

 very characteristic feature of this species. The nasals are long, narrow 

 and splint-like, and to their anterior broadening is principally due the 

 spatulate shape of this portion of the rostrum. The premaxillaries are 

 very long and quite broad, but low dorso-ventrally ; the alveolar border 



