44 8 



RICHARD S. LULL 



with two rhinoceros-like horns, a larger one at the apex and a smaller 

 one on the summit of the hornlet. 1 



The missing portions of the skull have been restored from photo- 

 graphs of the American Museum skull No. 1081, already alluded to, 

 which were loaned through the courtesy of Professor Osborn. 

 The skull measurements are as follows: 



Premolar-molar tooth series - - - - - - o . 363 



Premolars --------- .139 



Molars ---------- .227 



Canine (crown) anterior length - - - - - .045 



Canine (crown) antero-posterior diameter - - - - .035 



Premaxillaries to condyles (estimated) - . 768 



Nasals to mid-vertex (estimated) - - - - - .740 



Transverse width of zygomatic arch - .583 



Depth of zygomatic arch (buccal process) - - - - .157 



Nasals, free length -------- .084 



Nasals, free breadth, --------. 140 



Outside length of horn ------- . 1 70 



Expanse of horns _._-.----•-.. 393 



Those of the jaw are: 



Length, symphysis to condyle o . 685 



Premolar-molar tooth series - - - - -' .375 



Premolars --------- .140 



Molars ---------- .235 



Canine (crown) anterior length ----- .042 



Canine (crown) antero-posterior diameter - - - - .031 



Depth of jaw - - .355 



In the lower premolar series a tooth is missing on each ramus, on 

 the left the first, and on the right the second premolar, the missing 

 ones being indicated by their roots. The molar series is well devel- 

 oped below and above, the hypocone of the third superior molar 

 being well formed. 



The atlas. — -The atlas is a broad, heavy bone, with wide articular 

 facets and expanded transverse processes. The spine is extremely 

 low, and the short truncated hypopophysis extends backward. Of 

 the foramina, only that for the dorsal root of the first cervical nerve is 

 present, the ventral one, well shown in Palaeosyops, 2 being here 



1 Restoration of the Titanothere Megacerops. R. S. Lull, American Naturalist, 

 Vol. XXXIX (July, 1905), p. 423, Figs. 2, 3. 



2 Charles Earl, Journal of the Academy of Natural Science, Philadelphia, Vol. IX, 

 2d series, Art. VI, p. 294. 



