STEXEOSAURCTS. 99 



series the base of the transverse process rises a little on the arch, to the anterior edge 

 of which it reaches, though separated by a short interval from the posterior edge ; the 

 basal portion of the process is nearly horizontal and is strongly compressed from above 

 downwards, this character being more marked towards the hinder end of the series. 

 The separation of the parapophysial and diapophysial parts of the process is marked on 

 the ventral surface by the presence of two rounded ridges running out to the articular 

 surfaces and separated by a shallow groove ; this separation becomes less distinct 

 in the posterior dorsals, where the parapophysial surface forms a mere step on the 

 anterior edge of the compressed, broad, and here shortening diapophysial process 

 which bears at its extremity the surface for the tubercle of the rib. As in the anterior 

 dorsal, so in the rest of the series, the transverse process is gently convex above and 

 concave below, and is directed a little backwards. 



The neural spines (n.sp.) vary a little in width and height in the different species. 

 In all they are broad, slope a little backwards, and terminate above in a straight 

 border, which is thickened and raised into a series of ridges running down the sides of 

 the spine ; this thickening and roughening is, no doubt, correlated with the support of 

 the dorsal scutes. The anterior zygapophyses (a.z.) are separated by a deep groove for 

 the attachment of ligament; they are larger in the anterior than in the posterior 

 dorsals. The posterior zygapophyses (p.z.) are separated by a deep pit, into which 

 probably a ligament was inserted ; their upper edge is continued backwards on the side 

 of the arch as a slight ridge which may extend down to the posterior border of the 

 transverse process; their articular surface is sometimes a little concave from side to side. 



The number of the lumbar vertebrae is not certain. In no skeleton in the 

 collection have more than two been observed that can be definitely assigned to this 

 position. Their general form is similar to that of the dorsals, except that the transverse 

 processes bear no facets for ribs ; in one case it appears as if a short rib may have been 

 fused with the outer end. The posterior face of the centrum of the last lumbar is much 

 wider in proportion to its height than in the vertebras in front, and though still 

 somewhat concave is slightly bevelled off at its sides to fit the concavity of the firsc 

 sacral. The neural spine is nearly vertical and greatly thickened at its summit, which 

 is occupied by a smooth convex surface, beneath which the sides of the spine are raised 

 into numerous prominent ridges. 



There are two sacral vertebras ( PI. VI. figs. 6, 6 a), which are modified much as in 

 recent Crocodiles. In the anterior sacral the anterior portion of the centrum is deeper 

 and broader than it is at the posterior flattened surface for union with the second sacral. 

 The anterior surface for union with the lumbar is wider than high, and concave, especially 

 from side to side ; its upper and outer portion in some cases is formed by a facet borne 

 on the base of the sacral rib (PI. VI. fig. 6 a), which unites extensively with the side of 

 the anterior portion of the centrum. The posterior articular surface of the anterior 

 sacral is, as already noted, much smaller than the anterior, and is circular and nearly fiat. 



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