THE MICROSAURIAN FAMILY UROCORDYLID^. 



119 



(347) in his specimens. On the other hand, I find a normal microsaurian pectoral 

 arch (464) , such as has been described for numerous other forms. There are present, 

 distinctly preserved in the type specimen, the scapulae, the clavicles, and the interclav- 

 icle, with the possibility of the coracoid. The peculiar element referred to by Cope 

 as resembling a "lacertilian pubis" is without doubt the left scapula of the animal 

 (plate 1 6, fig. i). Its form compares very favorably with that of Ceraterpeton as fig- 

 ured by Woodward (630) . The coracoid may be represented by the fragment which 

 lies close to the scapula. The sculptured element lying next to the supratemporal 

 horn of the skull is the right clavicle preserved bottom side up. Of the other two 

 sculptured elements, one is the interclavicle, only a portion of which is preserved. 

 The left clavicle lies beside it. The clavicles in this species have a tendency to 

 assume the triangular shape so common in other species of Microsauria, and the 



pmx 



FIG. 24. 



A. Skull of Diceratosaurus lavis Moodie, from the Linton Coal Measures. X I. /, frontal; 

 j, jugal; mx, maxilla; n, nasal; or, orbit; par, parietal; pof, postfrontal; po, postorbital; 

 pf, prefrontal; pp, postparietal ; sq, squamosal; spt, supratemporal; qj, quadratojugal ; 

 pmx, premaxilla; tab, tabulare. 



B. Reconstruction of skull outlines of Diceratosaurus robustus Moodie, from the Coal 



Measures of Ohio. X 0.75. fr, frontal;./, jugal; or, orbit; par, parietal; pof, postfrontal; 

 po, postorbital; pp, postparietal; qj, quadratojugal; spt, supratemporal; tab, tabulare. 



interclavicle, so far as can be determined, was shield-shaped. The upper sur- 

 faces of the pectoral elements are marked by grooves for the attachment of the 

 pectoral muscles. 



The ventral scutellation is present in a small patch (plate 16, fig. i) near the 

 horn of the skull. The scutas are oat-shaped and take the usual form. The ribs 

 are not long, are rather stout, and beyond the proximal curve are nearly straight to 

 the obtuse tips. The heads of the ribs are so obscure that it is impossible to deter- 

 mine whether they were two-headed or not. They are expanded proximally and 

 there is a slight tendency to a division of the head. 



Portions of both fore limbs are preserved. The right limb possesses the hume- 

 rus, separate radius and ulna, and 2 metacarpals. The other possesses only the 

 radius, 3 metacarpals, and a portion of a phalanx. The humerus is a very stout 

 bone and at once recalls that of Amblyrhynchus. The ends are expanded and there 



