EDENTATA OF THE SANTA CRUZ BEDS. 323 







PLANOPS MAGNUS sp. nov. 



(Plate LVIII.) 



This species may be recognized by its very large size, for it is one of 

 the largest known Santa Cruz Gravigrada, by the length of the rostrum, 

 and by the more rectangular, less oval, shape of the upper molariform teeth. 

 The type is a well-preserved skull (No. 15,346), lacking the premaxillae, 

 jugals and mandible, which was found by Mr. Hatcher at Killik Aike. 



The caniniform (- 1 ) is small, recurved, of longitudinally elliptical section, 

 and with nearly horizontal masticating surface; a considerable space 

 separates this tooth from -, but the distance in front of it, to the anterior 

 edge of the palate, is more than twice as long as the diastema ; * is trans- 

 verse and molariform, longer antero-posteriorly than any of the other 

 teeth and narrower transversely than any except -, and is of an irregu- 

 larly quadrate shape ; - is broad and antero-posteriorly compressed and 

 more nearly rectangular than any of the others ; - is like a , but slightly 

 smaller and less regular ; A is much smaller and with reniform grinding 

 surface, owing to the posterior vertical sulcus. 



MEASUREMENTS. 



Upper dentition, length 062 i, length 009 



" 2-& 040 " width 012 



Distance from J- to anterior edge of ^ length 009 



maxillary 036 " width 014 



Diastema between i and -2., length 017 -i, length 008 



JT, length (t. e., antero-posterior diam- " width 013 



eter) 008 & length 007 



1, width (z. e., transverse diameter)- . . . .0063 " width Oi I 



In most of the Santa Cruz Gravigrada the highest point in the upper 

 contour of the skull is the parietal eminence, which is in nearly the same 

 vertical line as the glenoid cavity. In the present species, however, the 

 upper contour is nearly straight, the rise from the occiput is very slight 

 and the highest point is not in the parietal, but in the frontal zone, a 

 little behind the orbits ; from the summit forward is a long and gradual 

 descent. Except for the descending side walls of the posterior nares, the 

 dorso-ventral diameter of the cranium is nearly uniform throughout, while 

 that of the face diminishes anteriorly. Viewed from above and disregard- 

 ing the zygomatic arches, this skull appears like an elongate, slightly 



