MEGALOJSTYX LEIDYI, TST. SP. 



9 



ment of his admirable work on the osteology of the fossil Edentates — one of the 

 numerous fields in which his master mind has illuminated the way on which humbler 

 servants of Science endeavor to follow his lead. 



Comparative Measurements of the Skulls of Megalonyx jeffersoni'- and M. leidyi. 



M. jeffersoni. M. leidyi, 

 Owen Spec. Dickeson Spec. Kansas Spec. 



Length of skull from occipital condyles to anterior margin of 1st mm. mm. mm. 



molar alveoli 356 336 843 



Lengtli from inion to anterior margins of nasals 311 .... 309 



Length of temporal fossa to postorbital protuberance 197 197 199 



Depth of temporal fossa in a straight line 103 114 108 



Length of face from postorbital protuberance 119 112 115 



Height of face to middle of hard palate^ 153 146 136 



" at anterior extremity ...137 127 101 ^ 



Breadth " " " 95 95 83 



" " at sides of 1st molar alveoli 114 114 101 



" " at postorbital protuberances. 127 138 123 



Diameter of orifice of the nose 89 89 77 



Breadth of intermaxillaries, across their centres 85 * 45 ' 



Breadth of hard palate between 1st molars 60 f 40 



Length of interval between 1st and 2d molars 50 f 40 



Length of face from 1st to last molar alveolus 178 171 150 



Length of maxilla from 2d to 5th molar alveoli, inclusive 95 f 95 * 80 g 



Breadth orcranium at narrowest part of the temporal region 89 103 91 



Length of sagittal crest 127 127 144 * 



Height of inion from inferior margin of /oramere wiap'ftMm 110 110 107 



Breadth of inion at mastoid processes 159 165 165 



Capacity of brain cavity, 448 cu. cm. This indicates the weight of the brain to have been 16 oz. 

 (according to Owen's rule : Gomp. Anat. and Physiol, of Vertebrates, Vol. iii, p. 144 ; the 

 footnote) . 



' According to Leidy [I.e. p. 13), unless otherwise stated. His measurements, in inches and lines, have here 

 been reduced to millimetres. 



' This measurement is talien in a vertical plane passing close in front of the anteorbital borders. 



^ Although the intermaxillary bones are missing, the areas of their attachment to the maxilla are well marked. 



* The anterior terminus of this crest is determined somewhat arbitrarily, the parietal bones leaving a wide 

 fissure between their margins, which gradually diverge and pass over into the ridges curving outward and forward to 

 the postorbital protuberances. 



* Measured on Leidy's plates. 

 •I- Measured on a plaster cast. 

 § Estimated. 



A. r. S. VOL. XVII. B. 



