38 



face of the latter is crescentic, with an angle on the outer anterior border. 

 This angle is the summit of a short low rugose ridge, which extends part 

 way to the knob. Outer edge only of the great ala radiate grooved ; 

 posterior angle of distal condyle produced. 



The dorsal vertebra is somewhat flattened by pressure ; but the bal- 

 was evidently transversely cordate in outline. The bases of the dial 

 pophyses are very rugose; an acute angle from the articular cartilage is 

 directed toward it from the rim of the cup. Inferior face with an obtuse 

 median keel. The odontoid bone is deeper than long (fore and aft). 



As compared with L. micromus, this species differs in the much less 

 attenuated premaxillary and maxillary bones, the anterior nostril, and 

 absence of facets on the crowns of the teeth ; from L. proriger in the 

 absence of nan-ow concave facets on the anterior teeth, and anterior 

 position of the nostril ; from L. dyspelor in the less compressed or less 

 knife-shaped dental crowns, and totally different form of the condyle of 

 the quadrate. 



Measurements. 



M. 



Length of bases of two premaxillary teeth 0.026 



Width of bases of two premaxillary teeth 034 



Length of bases of two maxillary teeth . 042 



Depth of anterior suture of maxillary teeth 028 



Depth of maxillary at end of nares 038 



Length of quadrate 082 



Length of distal condyle 040 



Width of distal condyle 017 



Width of great ala on inner side 032 



Width of inner face above meatus 037 



Length of hook from stapedial pit 028 



Length of a dorsal vertebra 059 



Diameter of ball 



i vertical 029 



' \ transverse 048 



This species was discovered by Prof. B. F. Mudge, who dug the type 

 specimen from the gray shale of the Kiobrari Cretaceous, a half mile 

 south of the Solomon Eiver, Kansas. 



LiODON LATISPINUS, Cope, Proceed. Am. Philosoph. Society, 1871, 169, 

 and December. 



iTorth Fork of Smoky Hill and Trego County, Kansag. 



LiODON PRORIGER, Cop8, Transac. Amer. Philosophical Soc, Extinct 

 Batrachia, &c., 1870, 202 ; Macrosanrus proriger, loc. cit, on tab. xii, 

 figs. 22-24; Bhinosaurus proriger, Marsh, Amer. Journal Sci. Arts, 

 1872, June; Ehamphosaurus, Cope, Proceed. Acad. N"at. Sci., 1872, 

 141. 



Niobrara chalk of the region of the Smoky Hill Eiver, Kansas. 



LiODON DYSPELOR, Copc, Procced. Amer. Philosoph. Soc. 1870, 574; 

 loc. cit., 1871, December; Bhinosaurus dyspelor, Marsh Am. Jour. Sci- 

 Arts, 1872, 1872, June ; Tylosaurus dyspelor, Leidy, Eeport of Geolog. 

 Survey of Terrs., I, 271, tab. xxxv, figs. 1-11. 



jSTiobrara chalk of Fort McEae, N. Mex.; Niobrara chalk of Smoky 

 Hill, Kansas. 



