92 



A REVISION OF THE COTYLOSAURIA OF NORTH AMERICA 



The arrangement is shown in fig. 36, C and D. The teeth are bluntly conical with 

 no anteroposterior cutting edges. The enlarged tooth is near the anterior end of 

 the maxillary series. There are no enlarged teeth in the lower jaw, and in neither 

 jaw can any trace of more than one row be made, but this is inconclusive, as such 

 teeth would be covered if present. 



pmx 



pm 



-psq 



\Sft 



C B 



Fig. 36. — Pariotichus brachyops. No. 4760. Am. Mus. 



A. Lateral restoration of skull. X i- p>"x, premaxillary; mx, maxillary; n, nasal; /, lachrymal; pj, pre- 



frontal; y, jugal; /, frontal; po, postorbital; p, parietal; sq, squamosal; psq, prosquamosal. 



B. Restoration of upper surface of skull. X f. Lettering as in A. 



C. Left side of same specimen as shown in D. 



D. Lateral view of skull, xf . Lettering as in A. 



There is no resemblance between these skulls and those of the genus Capto- 

 rhtniis, though most of the skulls of the latter genus were originally described as 

 Pariotichus. As they form a distinct and separate group they have been placed 

 together in a separate family, Captorhinida. 



Measurements. mm 



Length of the type skull 22 



Width of same at back 22 



Length of skull of homotype 20.5 



Width at back 14 



Isodectes megalops Cope. 



Characteristic specimen: A small skull, No. 4329 Am. Mus. Nat. Hist. Cope 

 Coll. The skull is fairly well preserved and shows a fine reticulate sculpture. No 

 palatine teeth can be made out and the teeth on the premaxillary and the anterior 



Fig. 37. — Jsodectes sp. 



A. Upper view of skull, pmx, premaxillary; mx, maxillary; 

 n, nasal; /, frontal ; ptf, postfrontal ; pot, postorbital; 

 p, parietal ; /, jugal; sm, squamosal; st, prosquamosal; 

 soc, supraoccipital plates. After Cope. 



B. Restoration of skull according to the author, x $ This 

 restoration shows the skull too wide, as the bones have 

 been placed to show their full width. Lettering as in 

 previous figures. 

 C Lower jaw, showing numerous teeth. X ^. 



part of the maxillary are more sharply conical than those on the lower jaw. The 

 lower jaw has a prominent coronoid process and just anterior to this the dentary 

 is widened and there is a patch of small blunt teeth. They are partly obscured by 

 the matrix, so that the exact position can not be made out, but they seem to be irreg- 

 ularly arranged; in the anterior portion of the jaw is a single row of teeth. The 



