angle the frontal contracts, narrowing regularly to the line of the nares. 

 Theprefoutal has the remarkable form characteristic of Clidastes stenops, 

 that is with the exposed face sub vertical or steeply roof-shaped instead 

 of horizontal. A groove descends on each side to each nareal orifice, 

 and the intervening longitudinal ridge is deeply fissured by a parallel 

 groove. The parietal fontanelle is entirely iu the parietal bone. The 

 postfrontal is massive. 



The quadrate bone presents a very prominent internal angle as in 

 other Clidastes, and has the x30sterior hook much prolonged downward 

 and inward, with a button and surrounding groove on its inner side. 

 The stapedial pit is narrow oval, as in ^iodon proriger. The median 

 posterior ridge is prominent and united with the distal internal longi- 

 tudinal, extending to the narrow posterior angle of the distal articular 

 face. There is no internal ridge, but a strong obtuse ridge extends 

 along the outer side, turning backward into a rough process opposite 

 the origin of the base of the ala. Between this and the distal articular 

 face is a subtriangular rugose area.* The palatine bone has its an- 

 terior and posterior extremities broken away, the fragment supporting 

 six teeth. The bone is flat, much as in the species of Platecarpus, the 

 tooth-line passing from the inner margin behind to the outer before ; 

 the roots being more exposed on the external side ; the external process 

 is stout. The crowns of the palatine teeth are curved with lenticular 

 section, one face being much more convex than the other ; the enamel 

 is shallowly striate-groove. 



The articular faces of the cervical vertebrae are all transversely oval, 

 not much depressed ; those of the dorsals are also transverse, but less 

 so than the cervicals. Five cervicals and nine dorsals are preserved. 

 The hypapophyses, both fixed and free, are very lifrge and stout. The 

 odontoid is large and prominent, and deeper than long. The diapophy- 

 ses are short, and send a narrowed extension forward to the rim of the 

 cup on all the cervicals and three dorsals. The vertical portion of their 

 surfaces diminishes anteriorly as the horizontal extends, till, on the axis, 

 it is horizontally subtriangular in outline. The z^^gosphen is smaller 

 on the anterior than the posterior vertebrae -, on the latter the zygan- 

 trum possesses special facets for it. The cups, especially of the dorsals, 

 are emarginate for the neural canal. A smooth band borders the cir- 

 cumference of the ball in front. The surface in general is smooth, with 

 rugose lines and grooves extending to the articular face of the fixed 

 hypapophysis, and apex of the free, and on the upper roof-like surface 

 of the posterior zygapophyses. The inferior surfaces of the centra dis- 

 play a more or less prominent longitudial median ridge. 



* The uomenclatiu'e of these ridges is that proposed in the extinct Batraehia, etc., p. 

 183, with "internal" changed to external, and vice versa, in accordance with the ob- 

 servations of Prof. Marsh. 



