will 
IXTKODUCTIOX. 
condition of'llic sjicciinens cx;uniiicd is not favourable to its preservation. The canine 
and tiie tirst jin'inolars arc lost; the other prcinolars are evidently undergoing 
reduction, but at tlic same time the last has become bilophodont. The molars are 
all triloiihodont, each transverse crest consisting of at least two distinct tubercles; 
there is also a tendency to the addition of another posterior ridge from the cingulum. 
One notable point about tlie molar series is the sudden enlargement of the second 
and third true molars, compared with the teeth in front. This is accompanied by 
the considerable development of cellular tissue in the posterior part of the maxilla 
and the neighboniing bones, and appears to be the first indication of the great 
increase in the size of tlie posterior molars found in later types. This increase in 
the size of the maxilla, which is probably correlated with the general tendency of the 
bones of the posterior part of the skull to develop diploe, seems almost as if it were 
a pre])aration for the subsequent changes in the teeth, but, on the other hand, it is 
possible that the increase in their size may be in part a consequence of possessing 
more room in which to develojx 
As already noted, the mandible is greatly elongated in the symphysial region, and 
its- ascending ramus slopes backwards, both modifications tending to increase the 
distance the animal could reach with its lower incisors. Of these there is a single 
pair (the second) projecting forwards from the symphysis: the canines and first and 
second prcinolars are lost; the other premolars and molars are generally similar to 
those of the upper jaw. In the vertebral column the axis still has a peg-like 
odontoid process and a comparatively long centrum, though the centra of the posterior 
cervicals arc much shortened. The limb-bones, so far as known, are closely similar, 
except in size, to those of Flephas. 
In general appearance J^alaomasfodon must have resembled a small rather long- 
necked Elejihant, the most notable different'e fieing that the trunk, instead of lieing 
freely flexible, was supported by, and formed the upper covering of, the elongated 
mandibular symphysis ; its extremity, however, may iiave been free and to some degree 
prehensile. 
The further history of this group can only be briefly summarised here (see Phil. 
Trans. 19G b, 1903, p. 99). The next form, Tetr((heIodon angnstidens from the European 
Lower Miocene, has the sym})hysis still more elongated and the narial opening shifted 
further back. At the same time the molars, or at h ast the posterior ones, are greatly 
increased in size and possess more transverse ridges. There are three milk-molars 
in both jaws, and the posterior two are succeeded in the normal way by premolars ; 
