ise) 
[S) 
~I 
1872. ] [Cope. 
M. 
Length basioccipital to end muscular foramen............. 0.077 
by HyOManiGibilar 2 Lseae ser as Peas ee 226 
re inferior quadrate (Oblique) ....... 400 Ss Ae 
a condyle of quadrate..... A RS a zo iiss ABO 
Ks preopercurlum preserved........ oe OS hu. 7 Ue 
A portion of one of the flat unsegmented spines preserved exhibits an 
irregular rabbet on each edge of one side ; width, .042 M. The sclerotic 
bones are as already described. 
A second specimen is still stouter in proportions, as the following meas- 
urements show : 
M. 
Dismeter masilary condyle; < 36672 2.605 ee any oe se. 084 
Diameter maxilla above, behind condy le eats ee ae 035 
Length angle jaw (exteriorly):...2.... 0.2.2.6. 0 22s e ee 056 
Diameter parasphenoid at middle of predtic.......... Ses 5s QUO 
Diameter dorsal vertebra (crushed)....-. 2... agus... sve 6004 
The diameter of the vertebra must be a little corrected by reduction. 
The largest fish vertebree obtained may be here mentioned. They are 
peculiar in having numerous concentric grooves on the articular faces, as 
in Ischyrhiza. They are otherwise as in this genus. Length, M. 04; 
diameter, .062. 
A peculiarity of dentition is observable in the two specimens first de- 
scribed, and in less degree in P. molossus. A considerable number of 
alveole support no functional teeth (though included in the enumera- 
tion), but are occupied at some point by successional teeth. In some 
cases the mouth of the alveolus appears to be narrowed by ossification, 
even where the tip of the young tooth is in sight ; in one case so far de- 
veloped as to close up to the projecting apex. In other cases the orifice 
is entirely stopped by the ossification, which presents the appearance of 
a scar, with radiating lines of pores. 
The type specimen was discovered in a denuded area among the lower 
bluffs of Butte Creek. The flat cranial and jaw-bone occupied the sum- 
mit of a cone of twenty or more feet in height, a relic of the ancient blue 
limestone spared from the surrounding denudation. The flat bones had 
shed off the water, which, running off on all sides, had formed the cone. 
The second specimen came from the Fossil Spring Cation, near the 
remains of Liodon curtirostris. 
PoRTHEUS ANGULATUS. Cope. 
The crown of the tooth which indicates this species is slender, com- 
pressed, and curved backwards, and alittle inwards. The circumference 
is divided by two edges, the anterior acute, the posterior obtuse ; the 
convex faces separated by these are not equal, that towards which the 
crown is curved laterally, ¢. ¢., the inner, being somewhat more extensive, 
and considerably more convex 
A, P. §.—VOL. XII.—2Q. 
