TOXOCHELYID. 173 
plate Ixxxiii, belong to No. 1270. There appears to be no reason for doubting that these bones 
all belong to the same species. 
The principal differences between the present species and Cope’s T. serrifer must be sought 
in the form of the lower jaws and of the peripheral bones. Unfortunately we can not determine 
= ane: the form of the anterior nares of T. serrifer. 
Toxochelys Toxochelys Lhe lower jaw of T. serrifer shows no indica- 
ee : 
a serrifer. | stenopora. tions of a beak, while that of 7. stenopora 
Ss = —— (figs. 214-216) is plainly beakt. Case recog- 
Length from tip of jaw to hinder end nized this difference. The table herewith 
ce eee ma BON Oteaaes 48 33 presents the dimensions of the two jaws. 
| Width of grinding surtace.......... 9 6.5 : 7 
Winter iiss face at riddle of It is seen from these measurements that, 
Wet encte eee eens > 4 although the lower jaw of T. steno pora, as 
| Whole depth of jaw at middle ...... 8 9 represented by the masticatory surface, is 
Length of symphysis on upper surface 10 11.5 
much shorter than that of T. serrifer, the jaw 
is nevertheless deeper, the inner face of equal 
depth, and the symphyseal line of the masticatory surface longer. The width of the inner 
face of T. stenopora may be somewhat greater than the figures indicate, since there is evi- 
dence of some downward crushing. The symphyseal line above slopes downward and back- 
ward in J. stenopora; in T. serrifer, it is nearly horizontal. 
The peripherals of T. serrifer are much broader and flatter in proportion to their length 
than in 7. stenopora. Thus, in comparing what appear to be the eighth peripherals, we find 
that of 7. serrifer measuring 49 mm. in length and 32 mm. in width, while that of T. steno- 
pora is 23 mm. long and 10 mm. wide. 
The bones bearing the number 2060 of Kansas University museum are made the type 
of the present species, and in case it should be found that the skull and the other bones of 
2060 are not all of the same species, the former is to be regarded as the type. 
As will be seen from the figures (figs. 217, 218), the skull has been damaged, especially the 
hinder portion. Nearly the whole of the roof of the temporal region is missing. The quadrates 
and the supraoccipital are present, but detacht from the rest of the skull. Dr. Case’s figures 
represent the skull as larger by one-half than the originals; but this has probably been due to 
the failure of the engraver to reduce the original drawings. 
The skull was evidently short and bredd. The Hecance between the hinder ends of the 
maxillz equaled the distance from the snout to the middle of the basisphenoid; whereas in 
T. latiremis the distance between the extremities of the maxillz extends only to the narrowest 
portion ct the pterygoids. The length of the skull to the hinder border of the basisphenoid is 
46 mm.; to the occipital condyle was probably about 10 mm. more; while the length to the 
hinder end of the supraoccipital bone was about 82 mm. The palate, where narrowest, 1s 
10 mm. wide; the interorbital space, 13 mm. The alveolar surface of the upper jaw, including 
the rough ridge on the palatine, is rue ely broader than in 7. lJatrremzs, being contained in 
the length of the cutting-edge 3 times. In T. latiremis it is contained 4 times. This increase 
in the width of the surface appears to be at the expense of the fossa for the choanz, which is 
but little wider than the surface referred to; whereas in 7. latiremis the fossa is much wider. 
In the wideness of the alveolar surface and the narrowness of the fossa the present species 
resembles TJ. procax. 
There were without doubt posterior palatine foramina, as in the other species of the genus. 
That which distinguishes this species from all others of the genus, so far as known, is the 
narrowness of the anterior nares. ‘This slit-like opening is evidently natural, or due only very 
slightly to any compression during fossilization. The skull is flattened somewhat by pressure, 
from which condition we may conclude that the narial opening originally had possibly a more 
perpendicular position than at present. 
A portion of one parietal bone is among the remains of the skull. It presents a part of 
the roof of the temporal region. The supraoccipital (fig. 219) has a length of 35 mm. and a 
maximum height of 16 mm., being thus relatively long and high. 
This skull is accompanied by the pygal and nearly all of the peripherals of one side. Some 
of these have been figured by Dr. Case (op. cit., plate Ixxxiii, fig. 1). The pygal has a sharp 
posterior border and a rounded anterior border. From the latter there springs a process which 
