59 



the corresponding part of Monuclonius belli, described further on. In all other parts of 

 the crest the bone is thin, more particularly near and at the margin of the fontanelles 



Fig. 15. — Posterior crest of Monodonius dawsoni, viewed from beneath ; slightly less than one-eiglith natural size. The 



numbers give the thickness of the bone, in centimetres, at the points ind'oated. P, parietal ; S, squamosal ; F, 

 fontanelle. 



whilst along the sinuous curves of the sides the edge is sharp except in the emarginations 

 where it is rounded. Vascular markings occur on both surfaces, more particularly on the 

 peripheral projections. 



lleasurements. 



M. 



Height of orbit -110 



Width of orbit -095 



Height of horn core . 'SSI 



Circumference at base of horn cote . , ■ 343 



Antero-posterior diameter of base of same '135 



Transverse diameter of base of same ■ 092 



Diameter of occipital condyle " 060 



Length of maxilla approx • 350 



Height of same approx 120 



Long diameter of lower face of quadrate " 080 



Short diameter of lower face of quadrate " 036 



Posterior crest 



Extreme length from anterior end of specimen (imperfect), medially, to line 



touching posterior edges of specimen on either side •616 



Length on median line from anterior end to posterior border '486 



Semi-breath of specimen on curve of under surface ". . • 470 



Semi-breath of specimen horizontally • 439 



Vertical drop of lateral edge of specimen below median line of under surface 



at mid-length • 157 



Antero-posterior diameter of fontanelle '296 



Transverse diameter of fontanelle • 248 



Circumference of base of left posterior spur ■ 172 



