~ 
1884, | ‘ 41 [Cope. 
cranial region, zygomata, and left maxillary bone, have been lost. The 
measurements of No. 4 somewhat exceed those of the other specimens, 
80 that it is doubtful whether it really belongs here, 
The characters which distinguish this form from the J. leptorhynchus 
are not numerous. In the first place the front and muzzle are relatively 
wider. Secondly, the larmier is of a different form. Instead of being a 
horizontal slit, it is subtriangular, with the base above, and the angle 
below ; thirdly the canine teeth are more robust in both jaws, But the 
position of the infraorbital foramen is slightly variable, and the width of 
the front in one specimen is about as in the sub-species leptorhynchus. 
The size of the canine is not invariable. I am therefore precluded from 
regarding the M. leptorhynchus as more than a sub-species. 
As compared with the JZ elegans, the strong convexity of the side of 
the face distinguishes it. The convexity continues from the malar region 
forwards above the infraorbital foramen, and nearly reaches the nareal 
opening. Judging from Leidy’s fig. 11, Plate XI, of the Extinct Mam- 
malian fauna of Dakota and Nebraska, the premaxillary bone of the J. 
elegans is flatter than in the JZ arenarwm. The infraorbital foramen has a 
more anterior position in the latter than in the former. 
The size is always a little larger than in the type specimen of J lep- 
torhynchus. 
Measurements. M. 
ING ode 
Length from occipital condyle to postglenoid process... .087 
sy he A uy “ postfrontal process.... .076 
ut uk hi Ws ‘* preorbital border,.... .105 
(DYAMEVETse) GIBICUGL OF OL DIG isis viva tibee seule. wns vee ODO 
Depth of malar bone at middle of orbit. ...... seinen na OLD 
«© 7ygomatic process at glenoid face (greatest) .. .019 
Width at middle of supraorbital border, ...... . 062 
Oe aot) STEIN SONS E MN iin eae pales Cute SOU Her Meee 
‘+ © gygomatic process of squamosal. ........ see LOU 
| of octipital condyles... PC vec ren see OBS: 
My PV OCGLDUT HU MOLOCWOy.. ie diuties ce ee ae Se ENUOO 
Elevation of occiput including condyles. ...+++++...+5+ 054 
Depth of skull at right angles to profile at glenoid face. .041 
i ‘Vorbit (exclus, teeth)....... SO aot 051 
iH Of mandibular rAMUs AG Mees cee ee. ess .OBU 
Hi os Ore OTN lis Vie by 04 peneeuin cs 022 
Length of last five superior molars. ......-... Tiss ee UOw 
a CETUS MOUGTS, velavie eve dscns se ovieie yc ily eta Uae 
Dinmmeters Penis ANTETOPOSteLlOL. veseseveceeseveees -010 
CIATIBVELSO seve d tev va vse cues bs ce .010 
Diameters m. i j ANTETOPOSteLIOL ...cceeeses sevesecees .018 
WADSVOIRG Clu taebeb pene eelincwe ee One 
