234 S. W. WILLISTON. 



somewhat obliquely outward posteriorly. The squamosal and 

 quadrate, extending downward, forward and a little outward, meet 

 the cotylus of the mandible a little back of the middle of the 

 skull. Opposite the mandibular teeth in front are the narrow 

 maxillae, with teeth like those of the mandibles. They end freely 

 and acuminately behind, and if connected at all with the bones 

 of the upper part of the skull, the connection was small and 

 slender and situated far forward. The whole side of the skull, 

 from in front of the squamosal and quadrate seems to have been 

 unossified ; there are no jugals nor quadratojugals, and no tem- 

 poral arches. The premaxillae are also very slender, with four 

 or five small teeth on each side. The position of the eyes was 

 far forward, in the narrow space between the maxillae and the 

 prefrontals, and it is quite certain that these organs must have been 

 very small. The nares also must have been minute and situated 

 far forward, probably between the nasals and the premaxillae near 

 the middle line. Altogether, in life, save for its greater narrow- 

 ness and more snake-like appearance the whole head must have 

 been strikingly like that of Ncctiirus. 



VertebrcB. — The centrum is moderately elongated, deeply 

 biconcave with persistent notochord, wholly without trace of 

 hypocentra. In the middle below there is a median rounded 

 keel, concave longitudinally, with a deep pit or fossa on each side 

 reaching nearly to the internal cavity. On either side there is 

 another, more slender carina, bounding the fossa above, with a 

 more shallow concavity above it. The pedicel is elongate antero- 

 posteriorly, the neural canal large. The centrum has no para- 

 pophysial facet or process for the rib. A little below and back 

 of the anterior zygapophyses is the diapophysis, a flattened 

 process directed anteriorly and a little downward, with the ex- 

 tremity thickened and a little rounded ; they are short. The 

 arches are depressed, a little convex in the middle anteropos- 

 teriorly, but without spine, the two sides separated by a persistent 

 median suture, and the two bones are usually drawn somewhat 

 apart, like the bones of the skull. The zygapophyses are rather 

 large, flattened on their articular surface and are directed some- 

 what inwards or outwards. The ribs are large, flattened proxi- 

 mally, more cylindrical distally and are hollow. They have an 



