Cope.J 570 [Feb. 3, 



Leptophractus LINEOLATUS. Sp. IIOV. 



This large batracliian is represented by the middle portion of a cranium, 

 including parts of both jaws with numerous teeth. It is not easy to deter- 

 mine which of the tooth-bearing bones preserved is maxillary and which 

 dentary, but the lighter and thinner of the two is presumably the latter, 

 although it has tlie greatest vertical depth. The opposing bone supports 

 two types of teeth, and as this is only the case in the maxillary of Lepto- 

 phrdctus obsoletus, the present bone may be provisionally referred to that 

 position. 



There is a great difference in the sizes of the two types of maxillary 

 teeth, the larger having nearly three times the linear dimensions of the 

 latter. The small ones are rather distantly placed, being separated by in- 

 terspaces nearly equal to their lengths. They are cylindric at the base, but 

 become ccmipressed, and have two opposite cutting edges on the apical 

 third. They are of rather slender form, and are striate at Ihe base. The 

 longer teeth have a similar form, but are less strongly compressed distally, 

 where there are two opposite cutting edges. The basal portion is quite closely 

 striate. These teeth are on a different basal line from the small ones, since 

 when their bases are removed the latter appear behind them. Three smaller 

 teeth stand in the spaces between two large ones. 



The mandibular teeth are intermediate in size between the large and 

 small ones of the maxillary series, having a little more than half the linear 

 dimensions of the former. Their terminal three-fifths are compressed, and 

 furnished with fore and aft cutting edges. 



The surface of the bone, where visible, does not display the punctate 

 sculpture of that of the L. obsoletus, but is nearly smooth, displaying only 

 fine parallel incised strite. 



Measurements. M. 



Depth of dentary bone at middle 0:50 



Length of mandibular tooth 009 



Anteroposterior diameter of mandibular tooth at base. . . .0035 



Length of long maxillary tooth 022 



Antero-posterior diameter do. at base OOG 



Length of small maxillar}' tooth 007 



Antero-posterior diameter do. at base 002 



The smaller size and slender form of the smaller maxillary teeth, as wi'll 

 as the peculiar sculpture distinguish this species from the L. obsoletus. 



Another specimen of Leptophractus resembles the one above described in 

 the form and disposition of the teeth, and has the osseous surface of both 

 maxillary and dentary bones marked with shallow grooves and jninctate 

 impressions which do not inosculate. In this it resembles the maxillary 

 bone of the large specimen figured on Plate XXXVII of the second volume 

 of Paleontology of the Report of the Geological Survey of the State of 

 Ohio. 



