THE MICROSAURIAN FAMILY SAUROPLEURID.E. 169 



Leptophractus dentatus new species. 



Type: Specimen No. 10850, American Museum of Natural History. Col- 

 lected by Dr. J. S. Newberry. 



Horizon and locality: Linton, Ohio, Coal Measures. 



The type is a single right mandible, nearly entire, of a rather large animal. The 

 specific characters for the separation of the new form from the previously described 

 L. obsoh'tiis and L. lineolatus are 

 the smaller size and slenderness 

 of the mandible, associated with 

 uniform teeth, which are slender 

 and delicately fluted. 



There are 1 7 teeth preserved, 



. . FIG. 36. Mandible of Leptophractus denfatus new species, from the 



the largest Of which is 8 mm. Linton, Ohio, Coal Measures. X I. Original in American Museum 



i _, i -ci J.-L f Natural History. 



in length. From the posterior 



tooth the series gradually descends to half this length 0.5 inch from the anterior 



end of the mandible. 



The exact form of the mandible can not be determined, but so far as can be 

 seen it is very slender, coming almost to a point at the anterior end. The poste- 

 rior portion is wide, but apparently not very heavy. There is a fragment associated 

 with the specimen which discloses a few teeth, but its position in the cranium can 

 not be determined. 



MEASUREMENTS OF THE TYPE OF LEPTOPHRACTUS DENTATUS MOODIE. 



mm. mm. 



Length of mandible, as preserved 80 Length of most anterior tooth 4 



Anterior width of mandible 3 Length of tenth posterior tooth . . 7 



Posterior width 28 Width of this tooth at base 3 



Leptophractus llneolatus Cope. 

 COPE, Proc. Am. Phil. Soc., xvi, p. 576, 1877. 



Type: Specimen No. 1088 G, American Museum of Natural History. 



Horizon and locality: Linton, Ohio, Coal Measures. (Plate 22, fig. i.) 



Cope's description of this species, to which I have nothing to add, is as follows : 



' This species is based on portions of the skull of two individuals of large size. Both 

 upper and lower jaw with teeth are represented and the teeth are of very large size. The 

 deepest element preserved has been provisionally referred to the mandible and will be so 

 described. This element bears two types of teeth in very heterodont fashion. The teeth in 

 the back portion of the jaw are rather short and slender. The teeth more anteriorly are, 

 some of them, very long, rather stout, with their bases longitudinally fluted, as are they all v 

 The longest tooth in the jaw measures slightly less than an inch. The bone is not well 

 preserved, but seems to have been ornamented with grooves of no great depth. The most 

 anterior teeth of the jaw are smaller than the posterior ones. 



' The upper jaw is set with teeth which are more uniform in size and there is but little 

 tendency to heterodonty. These teeth are also striated at their base and all end in a sharp 

 point. They are all, apparently, straight. There is no tendency to curve as there is in the 

 genus Macrerpeton. The upper teeth are more closely set than are those of the lower jaw, 

 which are rather distantly placed. 



"Another specimen of a smaller individual presents the same portions of the skeleton 

 and the same characters. It is possible that this skull will be found to belong to Ichthycan- 

 tlius ohicnsis Cope, which is based on very large vertebrae and limb bones. The remains 



