THE MICROSAURIAN FAMILY SAUROPLEURID/E. l6l 



with its very long teeth. The skull of Sauropleura digitata Cope is not known, but 

 the body of that animal as preserved represents far too small a form for the skull to 

 be referred to that species. The skull is fully half as long as the dorsal region of S, 

 digitata Cope, so that an association of the remains would be incongruous. It differs 

 from the skull of 5. scutellata Newberry in size and proportions. The skull of S. 

 scutellata is narrow, while in 5. longidentata it is quite broad. The teeth of the latter 

 are also characteristic of the species, since in all other known species of this genus in 

 which the skull is preserved the large anterior tooth is wanting. 



The bones of the skull show the coarse sculpturing of the larger species of Micro- 

 sauria. It consists more of radiating grooves than of pits. The skull, as restored 

 (462), is broadly ovate, with the posterior border truncate. The muzzle is broad 

 and the nostrils are, apparently, located near the anterior margin. 



The posterior border of the orbits lies near the median transverse line of the 

 skull. They are circular and are removed some distance from the margin of the 

 cranium. Only the frontal and parietal can be determined with certainty. 



The mandible is heavy and is provided with pleurodont, heterodont teeth. Near 

 the anterior end of the mandible there is a very long fang-like tooth, longitudinally 

 striated and slightly recurved, which arises from a broad base and attains to con- 

 siderable prominence. The other teeth are smaller, though the next succeeding one 

 is still of considerable size. All of the teeth preserved are longitudinally striated, 

 but only the two anterior ones are recurved to any extent. 



MEASUREMENTS OF THE TYPE. 



mm. mm. 



Length of the skull in median line 75 Width of jaw, maximum 16 



Width of skull at posterior border, estimated 80 Width of jaw, minimum 5 



Width of skull across orbits 60 Length of largest tooth 1 1 



Width of orbit 10.6 Width of longest tooth at base 4.5 



Length of orbit 12 Length of shortest tooth 3 



Interorbital space 16 Width of shortest tooth at base I 



Length of jaw, as preserved 48 



Sauropleura foveata Cope. 



COPE, Trans. Am. Phil. Soc., xiv, p. 24, 1869. 



COPE, Geol. Surv. Ohio, H, pt. n, p. 406, pi. xxxvi, fig. I, 1875. 



Type: Specimen No. 8676 G and obverse No. 8675 G, American Museum of 

 Natural History. 



Horizon and locality: Linton, Ohio, Coal Measures. 



This species is represented by an interclavicle and its impression, which show a 

 beautiful sculpturing entirely distinct from that of the other species of this genus. 

 In size it is intermediate between the largest of the interclavicles of 5 1 . scutellata and 

 S. pauciradiata. The pattern of the sculpturing is, however, its main distinction. 

 The plate is finely pitted and there are few evidences of grooves. Near the posterior 

 border of the plate the pits become somewhat defined by ridges which take on a 

 radiating pattern with the center of the plate as the center. The beveled margins 

 are rugose, except at the edges. 



MEASUREMENTS OF THE TYPE SPECIMEN OF SAUROPLEI-RA FOVEATA COPE. 



mm. 



Median length of interclavicle 43 



Width of interclavicle, maximum 23 



