310 [ Dee, 7, 
Cope.] 
and a part of a mandibular bone with the last two molars in place, all be- 
longing to different individuals, The inferior sectorial tooth is much like 
that of the D. leptomylus, but the tubercular is only two-thirds as long, and 
is not only absolutely, but relatively narrower posteriorly. It has the 
usual three cusps in a reduced condition. In the first superior true molar 
the external cusps are conical, and there is a small cusp between the ante- 
rior one and the produced anterior angle of the crown, There is an ante- 
rior intermediate tubercle, but no posterior one. The cingulum does not 
extend all round the inferior base of the crown, as it does in D. protenus. 
The sectorial has a distinct anterior basal conic lobe. The internal lobe is 
in transverse line with the last named, and is conical and not large. 
Measurements. M. 
HiainGior taveriow deatoetal f anteroposterior.........- «¢ SOF8S 
transverse. ..esrenss  ehsie. ware QOBB, 
ay > aT 5 
Tiawieterinferianracercwlans anteroposterior...... veles ena 
UV ETBNIBV ODIO Wa siweeiieid view ee 00838 
Depth of Pam us. bt) Made cies rerieevewegemesiele sie ¥ als Veen VO0RS 
fs anteroposterior. .. .0110 
(transverse. ....... .0060 
anteroposterior . 0050 
transverse... 6. .0090 
Diameter superior sectorial (No. 1) 
Diameters superior sectorial (No, 2) { 
The fourth specimen is especially important as presenting almost the 
entire dentition including canines and incisors, and the anterior part of the 
skull from the line of the coronoid process of the mandible. The specimen 
shows that the species differs from the species of the Wasatch period with 
oval inferior tubercular, in the absence of the posterior cutting lobe of the 
third, and probably fourth inferior premolar. The corresponding superior 
premolars are also simple. The first premolars in both jaws are one- 
rooted, The canines are long and acute, and are directed vertically. Both 
have flat facets on their external (the only visible) faces: on the superior 
canine I count four lateral, and one nearly anterior. On the inferior I see 
three lateral and one nearly anterior. There are three small superior in- 
cisors, of which the first is the largest, and has a subconical crown. The 
infraorbital foramen is large, and is above the anterior border of the supe- 
rior sectorial, 
Measurements. M. 
Length of superior dental series to front of canine...... 041 
Mi € crown Of superio’ caning ......usere. Ebi aie « O11 
is "6 RUPOTIOL LIU MOlALS , cee veveceereseene ee [HOLUO 
Depth of ramus at inferior sectoral... ccccreseesececces 0090 
Tn its simple premolars this species agrees with the D. haydenianus, and 
is more primitive than the Wasatch species. 
TRIisODON RUSTICUS, Sp. NOV. 
Founded on a portion of the mandible which supports the first two true 
molars and part of the last premolar, The species is of the type of 7. 
