A NEW FOSSIL REPTILE FROM UTAH — GILMORE 



111 



The anterior caudal centrum, shown in figure 4, A, has quadrangu- 

 lar cupped ends and portions of heavy, transverse processes. The 

 ventral surface is shallowly channeled longitudinally. A second 

 caudal centrum (figure 4, B) is more elongated than the one pre- 

 viously mentioned. Its ventral surface is also shallowly channeled, 

 with distinctly developed chevron facets on the posterior end. It is 



Figure 2.— Centrum of ?axis of Pinacosuchuj 

 mantiensis, type (U. S. N. M. No. 16592) : 

 A, Ventral view; B, anterior view. Both 

 figures twice natural size. 



Figure 3, — Sacrum of Pinacosuchus mantien- 

 sis, type (U. S. N. M. No. 16592) : A, Ven- 

 tral view; B, lateral view; C, end Views. 

 All figures twice natural size. 



evident that this vertebra also bore transverse processes, thus indi- 

 cating that it belonged to the anterior half of the tail. 



Coracoid.— The articular end of a flat bone (fig. 1, B) perforated 

 by a circular foramen is tentatively identified as the proximal por- 

 tion of the left coracoid. Except for the scapular border being con- 

 vex, it has its closest resemblance with the coracoid of the crocodile. 

 It shows the same transverse thickening of the articular contribution 

 to the glenoid socket and the same hooklike process overhanging 

 the missing shaft of the bone, below the glenoid cavity. The place- 

 ment of the coracoid foramen is similar. 



Femur.— The bent shaft of a limb bone preserved with this speci- 

 men is provisionally identified as being that of a femur. It has a 

 large medullary cavity and at the center is round in cross section. 



Dermal ossifications. — The dermal armor of Pinacosuchus man- 

 tiensis displays no less than five different types of ossification : (1) 

 Simple, thin, flat, rectangular scutes; (2) ridged rooflike scutes 

 (fig. 5, C) ; (3) thickened subrectangular scutes, having sharp, asym- 

 metrically placed spine that strongly overhangs the borders (fig. 5, D) ; 

 (4) small pointed spines with thickened bases (fig. 5, A) ; (5) more 

 elongate pointed spines with thickened bases (fig. 5, B). All have 

 sculptured surfaces. 



