NK\\ I'l-.KMIAN VERTEBRATES 255 



elusion, we have only the genus Pnriofic/tns left, and in all its 

 characters, so far as the)' have been developed in tlk,- known 

 species of the genus, the agreement seems sufficiently certain. 

 Six species of ParioticJuts have been described. Of these', /'. 

 bractiyf>s is excluded by the large maxillary tooth not being 

 below the anterior border of the orbits, but much further forward, 

 by the relative si/e of the orbits, etc. I\ aguti is easily distin- 

 guished by the elongate shape of the head, its less depressed 

 form, etc. /'. isoloinns differs distinctly in its less expansion pos- 

 teriorly, its length being distinctly greater than its width, and the 

 absence of a posterior emargination of the cranial border. P. in- 

 cishns has been wrongly identified as having a single row of teeth 

 on mandibles and maxilla? by both Case and myself, whereas 

 Cope distinctly figures it (Trans. Auicr. Pliil. Soc., 1886, p. 290, 



FlG. 6. Life restoration of Pariotichus laticeps ; one fourth natural si/e. 



PI. II., Figs. 4 and 5) as having additional teeth. The form de- 

 scribed by me as Labidosaurus incisivus is therefore something 

 else. P. incisivus is described and figured by Cope as having 

 a purely reticulated sculpture of the skull, which he accepts 

 as of specific value. Our species has the sculpture, distinctly 

 longitudinal, on the upper side of the skull anteriorly at least. 

 P. adiincus is distinguished by the size of the orbits, etc. We 

 have, then, but a single species left, P. ordiuatus Cope, described 

 from such scanty material that it is doubtful if an actual com- 

 parison of the type specimen would resolve doubt as to its identity 

 with the species herein described. Our species may, therefore, be 

 provisionally given the name of P. laticeps. 



