PETERSON : NEW SULLINE REMAINS FROM THE MIOCENE OF NEBRASKA 315 
the teeth back of it and is implanted in the ramus by two fangs. The single pro- 
toconid is greatly developed, taking up the principal part of the crown. Antero- 
internally there is a minute cingular conulid ; while posteriorly the cingulum is quite 
strong. The external and internal cingula are wanting or only faintly indicated. 
Ps, has, as in pg, only the large protoconid with the anterior cingulum heavier and 
the posterior heel much better developed than in the tooth in advance of it. The 
external cingulum is strong, and internally there is no cingulum, except on the pos- 
tero-internal angle, which, together with the posterior ledge, forms a small basin on 
this part of the tooth. On py, the proto- and deuteroconids are closely fused, form- 
ing a cross-crest, which is much worn in the type. ‘There is a strong anterior base, 
and the metaconid is situated almost on the middle of the posterior base. No ex- 
ternal or internal cingula appear on this tooth. M, is too much worn for accurate 
description. There was evidently no external or internal cingulum on this tooth 
M, has the proto- and metaconids equally developed, while the paraconid is a 
minute element. Posteriorly the tooth is nearly as broad as anteriorly, the hypo- 
and entoconids being well separated. ‘The posterior and anterior cingula are heavy. 
The bottom of the transverse valley is filled up externally by the cingulum ; there 
are no other external or internal cingula on this tooth. Molars one and two in the 
mandible have a quadrate appearance, while ms; has a long sub-triangular form, 
which is due to the greatly extended posterior heel. The proto- and metaconids of 
the latter tooth are more elevated than the hypo- and entoconids. The postero-in- 
ternal angle of the heel is again elevated, so as to form a broad transverse valley 
back of the hypo- and entoconids. The heel is solidly fused. The open transverse 
valley between the proto- and hypoconids is taken up medially by the hypoconulid, 
as is indicated by the wear on the triturating surface. There is a heavy anterior 
cingulum. No other cingula are present on this tooth. 
MEASUREMENTS. 
SUPERIOR DENTITION. 
Totalilength ofthe upper!dentition -2.--..:1-..cs.s--se--ctseeiecereceseeeseecesbosatesscee 
Antero-posterior diameter of the three incisor alveoli. 
y i ( anterO-posteriOr........-2.:--scsssneseseeee senses Pee eeetcetes 
Diameters of the canine 1 t 
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Antero-posterior diameter of molar-premolar serieS ................cccecseeeceueseeees 
cb eG “cc 
“ the premolars 
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i ; ‘ 
Wi eth f BDCELO-POSLEM Ose arermennas sceetaccliccnndsncnece deere camaesmackineseerincere 1304: 
(ictransverse:eicrn ty teacamete ne Rh aries Sua chars i 06 
