61 



Thickness at lower end of glenoid cavity 



Thickness of coracoid in concavity below foramen . 



"Width of foramen ; inner end 



Height of same ; inner end 



Width of same ; outer end 



Height of same ; outer end 



•060 

 ■020 

 ■014 

 ■030 

 ■02.5 

 •040 



The sacrum plate XVI, figs. 1 and 2, is composed 

 of nine coossified vertebrEe, of •which seven are true 

 sacrals, the anterior one being a lumbo-sacral and the 

 ninth a caudo-sacral. Vie^wed from above its general 

 outline is seen to be some-what triangular, the apex 

 of the triangle pointing for-ward. 



The vertebrae have smooth concave sides and 

 under siirfaces and are swollen, •where they coalesce, 

 so as to form a prominent angularity marking the 

 line of union. The lower surfaces of the last five 

 vertebrte are fluted by a deep, median, longitudinal 

 groove that extends from the mid-leng:h of the fifth 

 vertebra back^ward to its termination in the ninth, 

 the groove being most pronounced at the vertebral 

 junctions. The first eight vertebrte give off seven 

 transverse, intervertebral processes that coalesce 

 distally so as to produce a strong bar whose outer 

 1 surface forms the iliac facet. Six openings are thus 

 , left bet^ween the iliac bar, the vertebral centra and 

 J the transverse processes. The posterior vertebra 

 gives ofi a simple transverse process. The junctions 

 of the second centrum -with the third, the sixth with 

 the seventh, and the seventh -with the eighth are 

 F:g. 16.— Sacrum provisionally associated with greatly enlarged by the increased do^wn^w'ard ex- 

 Monodonins dawsoni, less than one-seventh tension, at these poiuts, of the neurapophyscs from 



the natural size : superior view. i • i i , • ,-11 



■which the transverse processes spring ; particularly 

 is this the case -with- the second and third centra. The distance ol the iliac facet from 

 thenaedian, longitudinal line of the sacrum, dependent on the length of the transverse 

 processes and the breadth of the centra, is much greater posteriorly than in front; in its 

 anterior half the facet is directed obliquely downward, possibly with some exaggeration 

 due to distortion in the specimen. The iliac bar at its mid-length bends in-ward but 

 finally reaches the first vertebra by a convex curve. Seen from the side, the iliac bar is 

 horizontal throughout its length ■with the exception of an up^ward bend posteriorly. 

 Diapophyses spring from the neural arches above and are connected along the length of 

 their lower edges -with the transverse processes. Proximally the superior surfaces of the 

 diapophyses are expanded laterally so as to form a neural platform, the component parts 

 of ■which are not coossified. The prezygapophyses remain distinct from the postzygapo- 

 physes. 



The specimen has been somewhat crushed in a vertical direction. The diapophyses 

 have acted as vp'edges and have forced apart the halves of the transverse processes near 

 their basal origin. In figure 17, p. 62, the diapophyses are restored to their supposed 



