BAENIDZ. 83 
42mm. The postfrontal is large, having a length of 32 mm., being in contact by its lower 
border with the maxilla, the jugal, and the quadratojugal; and by its posterior border with 
the squamosal. 
The jugal is small, being only 8 mm. in length and 15 mm. in heigth. The squamosal forms 
the hinder border of the tympanic opening. Superiorly it has a thin crest, a relic of the former 
backward extension of the temporal roof. The tympanic chamber extends backward into this 
bone. The lower border of the zygomatic bar is considerably excavated. Seen from the side the 
maxilla is convex on its lower borden. From this border the bone rises 11 mm. to the orbit. 
The premaxill are distinct from the maxilla and from each other. At the symphysis they are 
only 3 mm. high, but at the union with the maxilla, 10 mm. high. As in the Bridger species 
of Baéna there are distinct lacrimal bones. The lower border of each comes into contact 
with the vomer. The jugals are excluded from the rims of the orbits (Plate 19, fig. 4). 
As seen from below, the maxilla has a broad masticatory surface, its width being 14 mm. 
from its inner border to the cutting-edge. The inner border of this surface is fairiisht by the 
palatine bone. The latter forms the whole of the outer border of the choana. The masticatory 
surface does not extend forward on the premaxilla. In front of the choanz there is a deep 
groove, which in front expands on the lower surface of the premaxilla. There are postpalatine 
foramina (Plate 21, fig. 2). 
The pterygoids come into short contact with the maxilla. They have distinct ectoptery- 
goid processes. Where the hinder part of the palate is constricted it is 18 mm. wide. The 
pteryg goids extend backward to the hinder border of the pedicel of the quadrates, thus sepa- 
rating the latter widely from the basioccipital and basisphenoid. ‘There is a considerable 
groove between the quadrate on each side and the median bones of the skull. The pterygoids 
join in the midline for a considerable distance in front of the basisphenoid. There is on each 
side of the latter bone, about the middle of its length, a venous foramen. 
The pedicels of the quadrates are short. The surface for articulation with the mandible 
is deeply concave from side to side, nearly plane from front to back. 
A pair of epidermal scutes appears to have occupied the space between the anterior 
halves of the orbits. Behind each of these and bounding the hinder half of the orbit was a 
smaller scute. A very large scute, or more probably a pair of them, occupied the area of the 
frontal bones and overlapt behind this on the parietals. The hinder half of this scute, or 
these scutes, if two, was separated by two median scutes. The more anterior of these last was 
circular; the more posterior was broadened backward and lay on the whole or part of the 
supraoccipital processes of the parietals. 
Eubaéna latifrons sp. nov. 
Figs. 69, 70. 
The specimen on whrch the present species is based was found by Mr. Barnum Brown, of 
the American Museum of Natural History, in Laramie deposits, on Seven Mile Creek, W yom- 
ing, about 40 miles northwest of Edgemont, South Dakota. It has the catalog number 6139. 
The specimen consists of the Silo without the lower jaw. This skull is crusht downward 
somewhat, and the right maxilla is forced inward partly over the triturating surface of that 
side. The left maxilla is missing. A part of the temporal roof is broken away and most of 
the supraoccipital spine is gone. 
It is not impossible that the shell of this species has already been described as one of the 
Laramie species of Baéna; but this can not be determined until the skull and the shell have 
been found together. The skull resembles that of E. cephalica; but a number of differences 
exist, which will be mentioned as the description proceeds. 
How far the premaxilla extended beyond the front of the nasal bones can not be deter- 
mined exactly; but the distance appears to have been less than in is ce phalica. It may be 
assumed to have been about 5mm. The length of the skull, from the front of the nasals to the 
occipital condyle, is 72 mm. The width from one quadratojugal to the other is 73 mm. 
Evidently the orbits looked upward less than in E. cephalrca, for the width of the interorbital 
space is 32 mm.; in E£. cephalica, only 25 mm. The horizontal diameter of the orbit is 17 mm. 
being thus more than in the species with which it is compared. The tympanic chamber, too, 
