DICOTYLIDE 291 
indiisting severe wounds with it: sharp tu:k:. A hunter who en- 
counters a herd cof them in a forest has often to climb a tree as 
his only chance of safety. Both species are omnivorous. living on 
roots, fallen fruits, worms, and carrion; and when they approach 
the neighbourhood «oi villages and cultivated lands ther ofter 
inflict great devastation upon the crops of the inhabitants. 
Remains of the two existing species of Peceary, a: well as of one 
much larger extinct form, are found in the cavern-deposiis of Brazil : 
while large Pecearies also occur in the Pleistocene of the United 
States. which, although ther have been referred to a distinct genus. 
Platygonus, on account of their relatively smaller incisors and some- 
what simpler premolars, may well be included in Dicstules. 
Allied Extinet Genert.—In the Tertiary deposits of both 
the Old and New World oceur remains of Pig-like animal: 
which, =9 far a: we can judge. appear to connect the Peccaries 
so closely with the true Pigs as to render the Distylida 
really inseparable Irom the Suma. Of these the American 
genus Chenohyus has the lower canine with a triangular cross 
ction and received into a notch in the upper jaw, a: in the Pec- 
caries, but the iourth upper premolar is simpler than the molars, as 
in the under-mentioned genus Hyctlerium. The trpical forms have 
ouly three premolars. but in others, which it haz been proposed ts 
separate generically as Bothriolalis, there are four of these teeth. 
Aystherium, ot the Pliocene 
and Miocene of the Old 
World, is a generalised 
form allied both to Sus and 
Dieotyles az wellas tw certain 
extinct genera. The upper 
molars (Fig. 119) are char- 
acterized by their square 
crowns, the last having no Fis. 110.—The three left upper molars of Hystherium 
distinet third lobe, and com- perimense, fro the Pliocene of India 
ing into use before the first is much worn, while the last premolar is 
simpler than the true molars. The canines, which have an oval section 
and are scarcely larger than the incisors, are not received into a 
notch in the upper jaw. In the Pliocene of India there occurs an 
apparently allied genus known as Hippohyus, in which the crowns 
of the molars are much taller, and have lateral inivldinys of the 
enamel, producing a very complex pattern on the worn crowns. 
The European Miocene genus Listriodon, with the dental formula 
i 4,¢4, p 3, m4, differs from all the preceding in having the 
anterior and posterior pairs of tubercles of the molar: united into 
ridges running across their crowns, 20 that these teeth resemble the 
lower molars of the Tapir. The genus is also found in the Lower 
Pliocene of India. 
