EDENTATA OF THE SANTA CRUZ BEDS. 255 



is moderately convex and of uniform width between the molariform teeth, 

 while the anterior part is flat and relatively narrow, in correspondence 

 with the slenderness of the rostrum. 



The mandible, which is represented only by the horizontal rami, lacking 

 the predental beak, is characterized by the external dental foramen, which 

 presents laterally rather than anteriorly and is placed at the base of the 

 coronoid process, somewhat more elevated than in H. forticiilus and 

 lower down than in most species of the genus. 



MEASUREMENTS. 



Skull, length in median basal line 109 Distance occipital condyle to glenoid 



" occipital condyle to anterior cavity. .021 



nares 127 " " " "A 062 



Cranium, length condyle to edge of orbit .095 Palate, length in median line 046 



Face, length orbit to anterior nares 032 " width at 1 016 



Occiput, height 036 " " " preorbital fossai 018 



width at base 050 " " " 1 oio 



Skull, width at postorbital constriction . . .030 " " " & oil 



" over lachrymals 044 Mandible, depth below -j 023 



Zygomatic arch, length 065 " thickness below y 013 



HAPALOPS PLATYCEPHALUS sp. nov. 



(Plate XLV, Figs. 1-3".) 



As the type of this species No. 15,564 will be taken, for that is the 

 most mature and best preserved individual of the series, although it has 

 suffered from oblique distortion. H. platycephalus is one of the smaller 

 species of the genus, about equalling H. elongatus in size, but decidedly 

 more robust ; it may be recognized by the short diastema between A and a , 

 the unusually flat palate, the short, wide rostrum, with deep preorbital 

 fossae, the broad, depressed cranium, without sagittal crest, and the low, 

 wide occiput, with very inconspicuous occipital crest. 



The teeth are of the pattern common throughout the genus ; i is not 

 preserved in any of the specimens, but the alveolus shows that it was 

 small and longitudinally oval ; this tooth appears to have been inserted 

 well behind the anterior edge of the palate, but the broken condition of 

 all the skulls renders this somewhat uncertain. After a rather short 

 diastema follows ^, which is ordinarily quite small and transversely rect- 

 angular ; is the largest of the series and -*- is slightly larger than ; ^ is 

 much reduced. The lower teeth, which are preserved only in the type, 

 have no striking peculiarities. 



