181 



SANIVA. 



Saniva ensidens. 



An extinct lizard, to which the above name has been applied, is indicated 

 by some remains discovered during Professor Hayden's exploration of 1870, 

 near Granger, Wyoming.' The remains consist of portions of a skeleton, in a 

 fragmentary condition, imbedded in an indurated ash-colored marl rock. The 

 bones are black, and the hollows of the long bones, including the ribs and 

 phalanges, are occupied with crystalline calcite. 



The remains belong to a lacertian about the size of the existing monitor 

 of the Nile, to which it appears to have been closely related. The bones 

 indicate a robust body, a long tail, and limbs with long toes. 



The vertebrae resemble those of the Nilotic monitor in form and propor- 

 tions, and like them possess no zygosphenal articulation. 



A pair of dorsal vertebrae are represented in Fig. 15, Plate XV. The body 

 is \ an inch long inferiorly, and measures § of an inch between the dia- 

 pophyses. The ball and socket extremities are twice the breadth of -the height. 

 The ball measures 4 lines in breadth and 2 lines in height. The neural arch 

 laterally at the zygapophyses is nearly 8 lines long. 



An anterior caudal has the same length as the dorsals, but is narrower. 

 The ball is of less width, but the same height. The hypopophyses for the 

 chevron are quite prominent, and are situated a short distance in advance of 

 the ball, as in the monitor. 



A small detached tooth, imbedded in the same mass, in proximity to some 

 small skull-fragments, presents the form and constitution of those of the moni- 

 tors. It is represented in Fig. 35, Plate XXVII, magnified eight diameters. 

 The length of the tooth is about 1^ lines; its breadth, :]- of a line ; and its 

 thickness, \ a line. It is compressed conical, feebly curved inwardly and back- 

 ward, sharp-pointed, has abruptly impressed trenchant borders, and is smooth 

 and shining. It is hollow, and has thick walls. The transverse section of 

 the base is rhomboidally oval, with acute poles. 



In breaking off portions of the rock containing the bones above described, 

 there was exposed what appears to be the anterior extremity of a maxillary 

 containing the remains of six teeth. The fragment is 4 lines long and \\ 

 lines deep. The teeth are pleurodont in character, but appear different in 

 form from the isolated tooth above indicated, and have more resemblance in 

 shape to those of the iguana. The specimen appears so small in its propor- 



