66 ; [Feb. 17, 
Jope.] 
Measurements. M. 
; saa de SPODOSTELLOL. os vccce eevee escsessesees .018 
Diameters m. lil < Antepopostene! : 
ViVATISVGISG, .cag oo. @ ee Ee eee Ole 
aid i anteroposterior....-sceeeeeeeee 019 
Diameters base of canine Raat komad: 
U4ranSVerse@ cscs « see es cet Ge NOU" 
As compared with the collared peccary this species has a skull of about 
the same size, but rather more robust. The posterior molars are consid - 
erably more robust. 
BOTHROLABIS Cope. Gen. nov. 
The species of this genus known to me differ as follows. It may be re- 
marked that they differ from those described by Marsh in their superior 
size. The latter are represented as being smaller, sometimes much smaller, 
than the common peccary. Those now described are equal to or larger 
than"that species. The type of the genus is the B. rostratus Cope. It very 
probably includes the Hyotherium americanum 8. & O.* 
I. Muzzle short; a rudimental second external cusp of superior 
p.m: 1. 
Superior true molars longer than space from m. i to canine; last superior 
molar wide as long; fourth inferior premolar one-rooted ; infraorbital 
foramen above middle of p. M. ie.seeeeeseeeeeseeces .B. subaquans. 
TI. Muzzle medium ; one external cusp to superior p.m. i. 
Superior true molars as long as space between p. m. i and canine ; inferior 
p.m. iv two-rooted ; infraorbital foramen above middle of p.m. is 
last superior molar longer than wide, with three cross-crests and no 
internal cusp at first valley.....-++.-sseeeeeeeceseeree .B. pristinus. 
Asin B. pristinus, but fourth inferior premolar with one root, and supe- 
rior m. iii with two rows of tubercles, and an internal tubercle at end 
of anterior valley.....-- Seach Vic ees Dee e ge oiet .... B. trichenus. 
TII. Muzzle long, compressed ; superior p.m. i with one external cusp. 
Molars small; true molars shorter than space from m. i to canine, last 
longer than wide, with two rows of tubercles; infraorbital foramen 
above middle of p.m. ii.....-.--- aia Giles B. rostratus. 
These species, with the Chenohyus decedens, form a series, which is 
measured by the increasing length of muzzle, and various other but con- 
sequent characters, One of these is the forward movement of the infra- 
orbital foramen, and the anteroposterior development of the fourth infe- 
rior premolar, In addition to these, the series displays a coincident 
posterior extension of the base of the zygomatic arch. In the C. decedens 
it is anterior to the posterior border of the last superior molar. In the 
Bothrolabis subequans it is opposite the same. In the B. pristinus it is 
posterior, and in B. rostratus, very much posterior to the last superior 
molar. 
* Preliminary account of fossil Mammals from the White River formation; Bullet. 
Mus. Compar. Zodl., Cambridge, xiii, 5, p. 155, 1885. 
