PLATE XXIXc?. 



Fossils of the Puerco epoch, natural size, except Fig. 9 a. 

 Fig. l.—PantoUmbda eaririclus Cope, right mandibular ramus, external side; a from above. 



Represented by a nearly entire mandibular ramus with all the teeth represented excepting the 

 crowns of the incisors. The characters are seen, first in the large size, the teeth having twice the 

 linear dimensions of those of the P. hathmodon ; and second, in the lateral prominence of the inferior 

 edge of the ramus, which produces a concavity of the side of the jaw posterior to the canine teeth. 

 It is the largest mammal known from the Puerco formation. 



The inferior canines are strongly curved, so that the crown is directed upwards and a little back- 

 wards. Both root and crown have a round section, but the apex of the crown cannot be described, 

 as it is greatly worn by use in the specimen. The incisive border is regularly convex, and the 

 three incisors are not of large size, the first being least, and the third largest. The premolars and 

 molars have the form of those of the P. hathmodon. The latter present two V's, the anterior nar- 

 rower and more elevated. In the former the posterior V is represented by a short crest. The last 

 molar is produced into a heel, which supports the posterior branch of the posterior V, and no cusp. 

 The first premolar is one-rooted, and is separated from the second premolar by a moderate diastema. 

 The symphysis is not long, is regularly curved upwards, and has a flat inferoanterior face. The 

 cauine alveoli create a marked prominence on each side. 



ifeas«remen(3.— Depth of ramus at diastema, m. .045; do. at third premolar, .056; width of ramus 

 below third premolar, .021; length of bases of three incisors, .023; diameters of canine at base: 

 anteroposterior, .018; transverse, .018; diameters third premolar: anteroposterior, .012 ; transverse, 

 .Oil; diameters first true molar: anteroposterior, .077; transverse, .014; diameters third true 

 molar; anteroposterior, .022; transverse, .014. 



The jaw of this species is about the length of that of a large tapir, but is deeper and more robust. 

 The flare of the inferior edge in front is suggestive of the structure seen in the Divocerata, and of 

 the probability that the Taligrada (to which Pantolambda belongs) are the ancestors of that sub- 

 order as well as of the Pantodonta. The flare is related to the flange of Uiutatherium, exactly as 

 the similar ridge in Nimravus is to the flange in Machsrodus. 

 Figs. 2-6.— Co«ari/c(es ditrigonus, parts of three individuals, viz, fig. 4 of an immature animal, and the 



other figures of two adults. 

 Fig. 2.— Left maxillary with teeth, the fourth premolar belonging to a separate individual from that 



which has furnished the remainder of the specimen. 

 Fig. 3.— Fragment of mandibular ramus with last two true molars, from above, probably from tUe indi- 

 vidual which is chiefly represented in Fig. 2. 

 Fig. 4.— Right maxillary with three deciduous and one permanent molar in place, from below. 

 Fig. 5.— Head of tibia of individual represented in Fig. 3, proximal view. 

 Kg. 6.— Distal end of tibia of Fig. 5, anterior view ; a, distal view. 



These specimens were received too late for insertion in the body of the work. They indicate 

 that the species must be referred to the genus Comrycteg Cope, and render it very probable that the 

 genus belongs to the family of the Periptychidse. The absence of ungual phalanges prevents abso- 

 lute certainty. The genus is near Periptychm, but differs in the one root and simple conic crown of 

 the second true molar in both jaws, and the presence of cingular cusps of the superior molars, 

 exterior to the external tubercles. Conwyctea ditrigonus has the molars of both jaws larger than 

 those of the C. comma, and there is less difference in size between the posterior and anterior true 

 molars than in that species. 



