PROF. OWEN ON THE ENDOTHIODONT REPTILIA. 561 
The median line of the palate, in Endothiodon uniseries, describes 
a strong sigmoid curve, concave downward at its anterior half, convex 
at its middle to where the vomerine plates (13) pass into the palato- 
naris (p n, fig. 3). This aperture is single, pyriform, about an inch 
broad at the part preserved where the skull has been broken 
across. The narrower fore part is partially divided by the vomer 
(ib. 13), which sinks into the opening as the palate is viewed from 
the basal aspect shown in fig. 3; and there the two thin vertical 
lamellee divide the nasal passages. The common hinder aperture 
beyond is bounded laterally by the thick and deep pterygoids (24). 
The vomerine lamellee, as they emerge at the fore and narrow part 
of the palato-naris, become thickened, with smoothly rounded palatal 
margins, and are divided by sutures from the intervening perforated 
palatal process (a p) of the premaxillary. 
The pterygoidean side walls of the palato-naris (ib. 24), smoothly 
concave mesially, swell out upon the palatal surface into irregularly 
convex tracts, 1 inch 4 lines in length, 7 lines in breadth posteriorly, 
and gradually narrowing to a point anteriorly, these pointed ends 
being divided from the bilamellar vomer by fissures (ib. f) conduct- 
ing to the palato-naris. The pterygoids are divided by a groove 
from the palatal bones (ib. 20), supporting the single row of palatal 
teeth. 
These teeth are nine in number on each side, disposed lengthwise 
in a slight curve concave outwards and parallel with that curvature 
of the alveolar border of the maxillary (ib. 21); from which border 
each tooth-series is separated by a shallow groove, 4 or 5 lines 
in width, along which extends the suture, of which the fore 
part is seen between 21’ and 20’, fig. 3. The teeth, which are all seen 
in transverse fracture, the crown-summits having been broken 
away, are subcylindrical in shape, composed of hard dentine, and 
without any exposure of a pulp-cavity at the line of fracture, 
which is nearly on a level with the supporting bone. The teeth are 
of equal or almost equal size, 6 to 7 millims. in diameter; the 
length of each series is 2 inches 4 lines, It is to be presumed 
that they were opposed by a similar single series on an answerable 
part of a broad upper surface of the dentary element of the 
mandible, since the number of palatal teeth, somewhat confusedly 
distributed in the type specimen of EH. bathystoma, indicates an 
arrangement in three longitudinal rows, as in the lower jaw, Pl. 
XXVII. fig. 1. 
The orbit in Hndothiodon uniseries (fig. 2, 0) is somewhat nar- 
row vertically at the fore part and gradually widens, as far as its 
bony boundaries haye been preserved, the lower one having been 
broken across at 2 inches distance from the fore part of the orbit, 
the upper one about 15 inch from the same part. The lower 
boundary extends outwards, and the fracture has taken place at the 
beginning of the zygomatic arch which supports a part of the 
malar (ib. 26). The upper boundary terminates behind in tho 
fractured surface of a tuberous and slightly deflected postfrontal, 12. 
Whether this was continued downward, as in Oudenodon (op. cit. 
