526. {Jan, 18, 
Measurements. ; M. 
Elevation of occiput from foramen........-+ decir LibgmeheN 084 
Width of occipital condyles....... sila a Wide vd lela aini owed 068 
Width of ‘oeciput at condyles. 2.20) i caicdiity le clot ww 095 
Depth of skull at right angles to profile at glenoid face. .095 
Be ae ne Re urate a orbit: sc ain OST 
aA ” at set) tus bs Pimrdaixvesie 075 
Length of superior dental series with canine..........5 159 
“ig of premolar series is said icici vinatav 1 OGY 
“ ue true Molar seriesy visu. oe. ok. s wiry!) O65: 
Giemeters tts anteroposterior ........ Adal wats Wid Dei .. 0180 
Uitransiversensial lobes weit’. senebade ievid KOLB 
iniotene or canine! anteroposterion se ciicidais iG. wales .016 
\ transverse. .... SOS RERE TNE fie at 020 
Dinctere Pan, a § anteroposterior. ...... wage ale veces 0155 
(transverse eis wuss Cociulanc000 
Widti of palatetatim dic ia. eigen wen WE SA 044 
an s PP at TO AOE abide Ai Stale! stbiiies a are\b 057 
The typical specimen was found on the John Day river, Oregon, by 
Mr. J. L. Wortman. 
Merycocheerus macrostegus, sp. nov. 
‘T have been able to discover in my collection as yet, but one cranium 
with entire mandible of this species. The very marked characters of this 
skull are such that no farther evidence of its reference to a peculiar species 
is needed. Its affinities, as expressed in the analytical key which accom- 
panies the general discussion of this genus, are with the MM. montanus. 
This is shown in the posterior positions of the infraorbital foramen, and 
of the posterior nares. As peculiar characters may be added the form of 
the frontal plane and of the otic bulla; also the prolongation of both the 
premaxillary and supraoccipital regions, and the forms of the zygoma, the 
angle of the mandible, and the first inferior premolar tooth. The skull 
reaches a greater length than that of any species, excepting the M. mon- 
tanus, but is not nearly so robust as in the M. chelydra, resembling in 
this respect rather the M. superbus. 
The muzzle is compressed, and there is a decided concavity just above 
the second premolar, above which the surface is a little convex. Above 
the infraorbital foramen, the face is abruptly convex, the convexity slop- 
ing upwards to the base of the median ridge formed by the convex nasal 
bones. Behind this the side of the face is a plane which slopes outwards 
as it descends, which is only interrupted by the rather small, but well de- 
fined, preorbital fossa. The fossa is better defined in front than in the other 
species, but I do not know whether the character is constant. The front 
is a transverse diamond-shaped area, bounded posteriorly by the anterior 
temporal ridges, and anteriorly by the lines of the supraorbital’ borders 
