ISTu.] '^ ' ' LCopi'. 



whose western extension into New Mexico, the present species is evi- 

 dence. 



LiODOiSr ICTEEICL'S, Copc. 



Char. External angle of the os quadratum close by the meatus, and 

 continued as a rounded ridge separating the anterior and external faces 

 of the bone. Median posterior ridge not prominent. Centra of dorsal 

 vertebrae depressed. Humerus broad, short. 



Description. This species is represented by portions of cranium, as 

 postfrontal, suspensorial, pterygoid, articular, and quadrate bones ; by 

 parts or wholes of several vertebras, which are all dorsals, and by scapula 

 and coracoid with many elements of the fore limb. The latter include 

 humerus, radius, a carjsal and numerous metacarpals and phalanges. 



The species is lirst well characterized by the form of the quadrate bone. 

 This element lacks a portion of the ala, and the postero-sviperior decurved 

 process, but is otherwise perfect. Its form is intermediate between that 

 in L. validus, Cope, and Mosasaurus depressus, Cope. Its external angle 

 of the pi'oximal extremity is posterior to its usual position, as in the 

 former species, but is less prominent than in it. It extends to near the 

 distal end, disappearing between the extremities of the median posterior, 

 and the distal longitudinal angles. The former of these is short, and it 

 disappears by a gradual descent distally, in a very rugose margin. The 

 distal longitudinal is short and acute, not prominent at the distal 

 extremity. From the posterior position of the proximal external 

 angle, the alar articular surface is somewhat elongate. The postero-ex- 

 ternal face above the meatus is proportionately short. The meatal pit is 

 scarcely one fifth the usual size, so far as determinable from the present 

 surface, but it is possible that the greater part is filled by an impacted 

 mass of bone derived from the adjacent ridge. The margins of the articular 

 extremities and of the ala are striate and x^apillose rugose. No meatal 

 knob. 



The suspensorium is slender. It is peculiar in the great extent of the 

 exoccipital element, which covers the whole superior surface, and extends 

 externally over the opisthotic to the squamosal, concealing the former ex- 

 cept its anterior margin. The jDrootic sends a small proximal portion 

 only to the superior face. 



The pterygoid has been free from its fellow medially. A distal and 

 median portions have been lost ; the remaining fragments present bases 

 and alveolse for eleven teeth. The fangs are rugulose and but little 

 swollen ; probably five to seven stood on the lost portions. The bases of 

 the crowns are circular. The external j^rocets of the bone is slender and 

 flat. 



The portion of the mandible preserved, includes much of the articular, 

 and adherent parts of the angular. The latter forms a narrow band on 

 the lower edge of the external face, and one twice as wide on the inner 

 face. The only characteristic feature is the lowness of the ridge which 

 descends and extends anteriorly from the anterior margin of the cotylus 

 for the quadratum. 



