SYSTEMATIC REVISION 47 



with the size of the skull. The enlarged anterior premaxillary teeth are not well 

 preserved, and their size is uncertain. In some other specimens of similar size 

 with rounded cross section of the muzzle, these teeth are enlarged as in P. aguti. 



"Measurements. 



"Length of cranium from line connection posterior borders of quadrates . . 0.162 



Length of cranium from middle of posterior border 145 



Interorbital width . 032 



Diameters of orbit: 



Anteroposterior 036 



Vertical .022 



Width of muzzle at posterior border of the nares 029 



Depth of muzzle at posterior border of the nares . 021 



Depth of the cranium at middle of the orbit . 035 



Length of crown of large maxillary tooth O06 



Depth of mandible at middle of orbit 020 



Length of mandible on ramus 170" 



On page 445 of the same article Cope gives an analytical table of species in 

 which L. (P.) hamatus is described as follows: 



"Orbit oval; cranium 162 mm. long, and nearly as wide; posterior border 

 emarginate; muzzle much contracted, entirely overhanging symphysis mandibuli." 



Later, in referring the species to the genus Labidosaurus, Cope added the fol- 

 lowing specific description : 



"Specimens since received display numerous characteristic pecularities not 

 preserved in the type. The sculpture of the cranial surface is in shallow fossae 

 with rather thick partitions, of smaller size than in the Pariotichus aguti, which 

 resembles it most nearly. Thus there are a dozen ridges between the orbits on 

 the frontal in the latter, while there are fifteen to seventeen in the L. hamatus. The 

 maxillary teeth are relatively smaller than in any of the species of Pariotichus 

 known, and they extend only to below the middle of the orbit. The orbit is sub- 

 round; in the type it is oval, perhaps owing to pressure. Its diameter is about 

 half the length of the skull, both anterior and posterior to it, and equals the inter- 

 orbital width. The nostril is anteroposteriorly oval, and the apex of the elongate 

 incisor tooth is below its anterior part. Thus, though the muzzle is more elongate 

 than in any of the species of Pariotichus, it does not project so far beyond the pre- 

 maxillary border. Length of the skull of the new specimen 155 mm." 



Revised description: The original description is adequate and correct. This 

 species differs from the following by the possession of but a single pair of enlarged 

 incisors in the premaxillaries instead of two pairs. 



Labidosaurus broilil sp. nov. 



Labidosaurus hamatus Broili, Paleontographica, Bd. ii, 1904, p. 51. 



This species resembles L. hamatus in most regards, but differs in the possession 

 of two enlarged incisors in the upper jaw instead of a single pair. Differences in the 

 skeleton are unknown. 



Hyponous squaliceps Cope. 

 Proc. Am. Phil. Soc., vol. xxxiv, 1896, p. 450, figs. 3-5, pi. viii. 



Type: Two skulls. No. 4335 Am. Mus. Nat. Hist. Cope Coll. From Texas. 



This genus was founded on a curious misunderstanding of the specimen by 



Cope. His original description of the genus reads as follows: "Nostrils on the 



inferior aspect of the muzzle. Teeth few, with compressed crowns. Cranial 



