The Skull of Labidosaurus. Gas. 
front of the middle of the nareal margins; and on the sides with the 
maxille, below the nares. The two bones together present a strong 
anterior convexity, with the alveolar border receding. Each has 
three, elongated, pointed, slightly recurved teeth, of which the inner- 
most 1s the largest, the outermost the smallest, less than half the length 
of the longest. In the closed mouth these teeth, or the inner ones, 
protrude quite a distance below the mandible, hook-like or rake-like, as 
shown in Plate II, Fig. 2. This extraordinary development of these 
teeth and their position, in association with the narrow, compressed 
facial rostrum, remind one strongly of the phytosaurs and are sug- 
gestive of like habits in the hving creatures, the exhumation of bur- 
rowing invertebrates from the mud or sand of the shores or shallow 
water. The maxille, free in one of our specimens, are rather slender 
bones, with their greatest width a httle in advance of the orbits. 
They extend back, decreasing in width, to nearly opposite the pos- 
terior part of the orbits, uniting above in front with the elongated 
lachrymals, behind with the anterior prolongation of the jugals. I 
count in different specimens seventeen teeth, not very different in 
size, the longest a little in front of the middle of the series, and the 
series separated from the outermost of the premaxillary teeth by a 
short diastema. The nasals form the upper side of the rostrum as 
far as their union with the frontals, a little in advance of the orbits, 
curving a little downward on the sides back of the nares, whose upper 
borders only, do they form. The prefrontals are subtriangular in 
shape and small; their inner sutures begin a little beyond the middle 
of the upper orbital margin and are parallel with each other, extend- 
ing a little beyond the end of the frontal bones. The lachrymals are 
large bones, united broadly with the nasals anterior to the prefrontals, 
and with more than half the length of the maxille below. They 
form the posterior boundary of the nares and the larger part of the 
anterior border of the orbits. The precise boundary between the 
nasals and lachrymals may be somewhat indefinite; the sutural line 
given is that in which four skulls seem to agree. The frontal bones 
have nearly parallel sides, extending posteriorly a little beyond the 
hind margins of the orbits, joining the parietals in a transverse ser- 
rate suture, which appears on the under side somewhat in advance of 
