Cope.] ^ ^ ^ [Jan. 7, 



Lines. 



Length centrum with ball 20.8 



" " to ball 18 



•' " " hypapophysis 5.8 



Width base hypapophysis 5.5 



Depth ball .' 10.4 



Width " 11 



" cup 12.6 



Depth " 11. 



Length base neurapophysis 12. 



In profile the ball has a very slight obliquity looking upwards. From 

 the Rotten Limestone of Alabama, discovered by E. E. Showalter, M. D. 



LiODON VALiDUs, Cope. 



Macrosaurus validus, Cope., Proc. Boston, 1869. Nectoportheus validus. 

 Cope, Proc. A. N. S., Phil., 1868, p. 181; Leidy, Cretac. Rep. 74-75, Tab. 

 VII, 19-20, III 12. 



This species is represented by two cervical and four dorsal vertebrae of 

 one individual, and a large dorsal of another, in the museum of the 

 Academy; the former associated with numerous fragments — including 

 part of an os quadratum, from L. T. Germain, Burlington co., N. J. Two 

 dorsal vertebrae of a large individual in the museum of Rutger's College, 

 several vertebrae with broken quadrate and other bones and teeth in my 

 private collection, from near Barnesboro, Gloucester co., N. J., and a 

 number of vertebrae in the collection of Prof. Marsh, of Yale College, 

 further establish its character. 



The quadrate hone is highly peculiar as above pointed out. The poste- 

 rior descending hook of the proximal extremity is quite shoi't, and is 

 marked by an obtuse ridge which passes forwards and disappears imme- 

 diately above the pit alongside the meatus. What especially characterizes 

 this species and genus, and allies it to Clidastes, is the presence of a 

 strong longitudinal angular ridge, which extends from the usual external 

 angle of the proximal extremity, (which becomes here a process, ) separ- 

 ating the outer aspect of the quadratum into two entirely distinct planes; 

 one that of the meatus, the other that of the ala. 



Two separate opistliotic bones accompany these remains, which were 

 mixed up with those of the M. depressus. The vertebrae of the two spe- 

 cies were easily separated. The quadrate bone also was identified by one 

 accompanying the vertebrae of M. validus, in my own collection. I could 

 not so readily assign the opisthotics to the proper species. I have assigned 

 them here, because their glenoid cavities apply much more readily to the 

 quadrate bone of the L. validus than of the M. depressus. As compared 

 Avith the same bones of two Mosasaurus dekayi, they present three 

 marked characteristics. First, they are relatively much shorter; second, 

 the distal anterior process which fits within the squamosal is much more 

 prolonged; third, the inferior of the two faces to which the squamosal is 

 applied, is a continuation of the general inferior plane of the bone ; in M, 



