972, 
Cope.] 272 Dee. 17, 
the inner basis of the zygapophysis and uniting with its fellow of the 
other side forming a production of the roof of the neural canal... The 
combined keels become continuous with the anterior acute edge of the 
neural spine. Thus the form is quite different from that seen in the last 
described species, and constitutes a lower grade of rudiment. The fact 
that this zygosphenal roof is separated on each side from the zygapophy- 
ses by an acute groove, gives the former a distinctness more apparent 
than real. 
The fixed hypapophyses are short and broad. The centra are not elon- 
gate. Those of the anterior dorsals present an obtuse keel below. 
M. 
Length of a median cervical. ......+-.++see cece eeee see eees 0.043 
: ae WOLMCUIN Top ese trite ee eta. 02 
Diameter of ball of do. | eeksievetis Eee oe: 033 
Length of anterior dorsal..........6- eee c eee e eee teers 042 
Width Of CUps Us ii ete eer ec wero rae rs Qewews tet oo oe 032 
Found by the author on a low bluff or ‘‘break”’ on Butte Creek, four- 
teen miles south of Fort Wallace. 
Hoxcopus IcTERICUS, Cope. 
ry 
Liodon ictericus, Cope, Proceed. Amer. Phil. Soc. 1870, p. 577. Hay- 
den’s Geol. Survey of Wyoming and adj. Terr. 1871. 
In adition to the two individuals of this species procured by Professor 
B. F. Mudge in one of his geological surveys, the writer obtained a con- 
siderable part of a third from a low bluff on Fox Cafion, south of Fort 
Wallace. This includes seventeen lumbar, dorsal and cervical vertebra 
including axis, with ribs, and a large part of the cranium with both quad- 
rates, occipital and periotic regions, etc. Its characters may be briefly 
pointed out as follows : 
Articular surfaces of dorsal and cervical vertebrae transverse oval, ex- 
cavated above for neural canal; diapophyses not extending below to the 
edge of the cup, hence not receiving an area of articular cartilage con- 
tinuous with the rim. Occipital crest low, oblique. Quadrate bone 
larger, the meatus depressed between ridges, A. button of articular sur- 
face on posterior face of hook. Scarcely any rudiment of zygosphen. 
Teeth small, much incurved, faceted and striate ridged. 
Some characters additional to those already derived from the first known 
examples may be added. The mandible supports only twelve teeth. The 
palatine bone is shorter anterior to the external process, and longer behind 
it than in H. corypheus. In our specimen, the posterior extremity is 
broken off, yet. shows no indication of the emargination for the ptery- 
goid bone an inch behind the position of its anterior extremity in H. 
corypheus. There are ten teeth on the part preserved, four in front of 
transverse process (six in H. coryphwus), and six (probably seven) behind 
(six in H. coryphwus). The plate is more expanded than in the last 
named species, especially the thickened inner margin, which only ap- 
a 
