384 Williston — Xnr Famil;/ of Reptiles from the 



skull is completed. The surface of the skull is almost smooth, 

 with feeble indications of small pits. 



The skull of Limnoscelis is remarkable among terrestrial 

 reptiles for its elongated form and highly developed incisor 

 teeth. The upper surface is nearly in one plane from the 

 margin of the occiput to near the extremity of the rostrum, 

 somewhat convex above in front of the eyes, and the parietal 

 region is moderately convex on the sides. Fortunately the 

 sutures of the skull nearly everywhere are quite distinct, even 

 visible in the photograph as serrated or zigzag lines. A few 

 cracks are present, but they are not confusing save in a few 

 cases, but those are in the most important part of the skull, the 

 posterior temporal and occipital region. The sides of the skull, 

 with the mandibles in place, are of nearly uniform height, that 

 at the nostrils being quite what it is at the temporal region, unless 

 there has been a slight depression in the latter place. From 

 just in front of the orbits the skull widens very rapidly, the 

 orbits themselves being nearly wholly concealed in top view 

 by the overhanging roof of the skull. In front of the orbits 

 there is a rather deep depression on each side. Back of the 

 orbits there seems to have been a nearly vertical wall for 

 some distance, and then convex broadly outward. The nares 

 are of considerable size, oval in shape and situated close to 

 the anterior end of the skull. The orbits are relatively small 

 and situated far back, the distance between orbits and nares 

 being greater than the extent of the skull posteriorly. They 

 are oval in outline, somewhat narrowed in the specimen, their 

 planes nearly parallel to each other and nearly vertical, the 

 posterior part turned a little outward. 



The premaxillae are very massive bones, strongly protube- 

 rant in front. The suture uniting them with the nasal is 

 strongly digitative, beginning at the front end of the nares. 

 Fach premaxilla has three large, conical and recurved teeth. 

 In the specimen the interior one on the right side had been 

 lost before fossilization, but its mate is complete; the second 

 and third teeth are successively smaller, but of the same char- 

 acter as the inner one, long, conical and recurved. The bases 

 of two are present on one side, with indications in the matrix 

 of their length. Doubtless when the skull is finally prepared, 

 the missing parts will be found. The long tooth lies in the 

 specimen as I have figured it, directed downward and back- 

 ward, and closely applied to the end of the mandible. 



The maxilla has quite the same relations as in the other 

 American cotylosaurs where it is known, a rather narrow bone 

 united with the premaxilla below the nares, with the lachrymal 

 throughout nearly its whole length above, and with the jugal 

 posteriorly below the orbit, which it joins by a long, oblique, 



