194 



THE EXTINCT BATKACHIA, KEPTILIA 



talis, is much suKillcr. -uid with ooSssifled chevron bones; it is without diapophyses and is henoe more posterior than 

 any of those of the present species here noted. It belongs to another species, but to -which of those here desoribed, If 

 to any, is difficult to determine. Dimensions of anterior oaudals of a large ? M. dekayi from the same position as 



those of M. mftximus. measured above: 



Lines. 

 Length of centrum, (anterior) 82 



Width articular face, 84.5 



Depth " " :!i) 



Length centrum No. 2, (a little behind) :> > ; S 



Width articular ball, :!8 



Depth " " 87 



A portion of the left pterygoid bone of the Bolmdel specimen above mentioned, exhibits parts and wholes of five 

 alveola;, and two teeth in place. In the latter the inner face is narrower than the outer, and they are separated in 

 the posterior tooth by a strong angulation. The small proportions of crown to root, as well as other details, are so 

 similar to those of the teeth described by Leidy as characteristic of Ids Baseodon reversus, that I have no hesitation 

 in referring the hitter as pterygoid teeth of a, large individual of this or another species. The teeth are of equal size, 

 thus differing from those of Liodon mitchttlii, and are much smaller in relation to the maxillary teeth than in tin; 



same. 



Lines. 



Length of whole tooth, pterygoid, '? 



Diameter fang, " "•" 



" crown, " 4- ,r> 



" " maxillary, 1(, - r> 



" fang, " Ui - 



The pterygoids are in a groove without alveolar septa. 



In addition to the characters already pointed out, this species differs from the M. missuriensis as follows, judging 

 from the figures and descriptions of Goldfuss. 



In M. dekayi the proBtic wraps over the opisthotio to its superior face; in M. missuriensis the exocoipital wraps 

 over to the superior face of the same bone. 



In missuriensis the squamosal forms a, horizontal three-cornered expansion and only touches the opisthotio behind. 



In M. dekayi the squamosal is largely inferior and has no superior expansion. 



In M. dekayi the under face of suspensorium is underwrapped by prootio, by the exoccipital in missuriensis. 

 Glenoid cavity two-thirds on squamosal in M. dekayi; not at all on squamosal in M. missuriensis. 



Lower (?upper) marl bed of upper cretaceous of New Jersey. 



MOSASATJRTJS KULCIATUS, Cope. 



Spec. nov. 



This species is represented by an os quadratum, three posterior dorsal vertebra, and an 

 imperfect humerus, obtained by Prof. Geo. II. Cook, from the Green Sand of Monmouth 

 Co., N. J. 



The vertebra' are those iii which (he diapophyses spring from the middle of the centrum, one being quite flat- 

 tened, and the other triangular in section. The centrum is convex below them; the articular faces nearly round. 



The prominent peculiarity is seen in the os quadratum. The ala is broken off . The external angle is consider- 

 ably smaller than in M. dekayi, I hough not more so than usual variation would allow. The knob is very promi 

 nent, and is separated by a deep groove from an elevated ridge, which extends from the pit and terminates in a. 



rugose prominence representing the process in M. maximus ; (see plate xi, f. 7). Anterior to this, another ridge 

 arises from tin; rugose muscular insertion and extends t<> (he extremity of the bone diverging from the first men- 

 tioned ridge, constituting the externa] distal ridge; the space between these ridges is filled up, and the section across 

 them is that <>f a prominent rectangular buttress; a, wide concavity separates ii from tin; external surface of the ala,. 



