MACROPODID.fi. 
52 
the mouth is closed, the outer cutting edge of the lower inci¬ 
sors is brought in contact with the cutting edges of the two 
posterior incisors of the upper jaw on cither side, and their 
points shut within the apex of the foremost pair of the upper 
jaw. In Macropus major (and perhaps in some nearly 
allied species) the rami of the lower jaw arc loosely attached 
at the chin, and at the apex they are free, and the animal has 
the power of slightly separating the lower incisors, so that 
their outer cutting edges are brought more closely in contact 
with the upper incisors than they otherwise would he. The 
foremost of the molar series is a false molar, and differs in its 
form from the others, being laterally compressed: it sometimes 
has an indented fold of enamel both on the outer and inner side, 
in or near the middle of the tooth, die crown of which is thus 
divided into two parts, which are equal in length, but the pos¬ 
terior half has a greater transverse diameter. The true 
molars differ somewhat in size, there being a slight and gra¬ 
dual increase in size from the foremost to die last: the crown 
of each molar presents nearly a quadrate figure, hut is longer 
than broad; it has two principal transverse ridges, which,before 
worn, are considerably elevated, and have trenchant edges; 
the foremost of these ridges is evidently formed bv the junc¬ 
tion of the anterior pair, and the hindermost by the union of 
the posterior pair of cusps, which are most commonly seen in 
complicated molar teeth, and which wo find much less per¬ 
fectly joined in the Kangaroo-rats. Besides diesc two prin¬ 
cipal eminences, are two other transverse ridges, which are 
smaller and less elevated; one is situated on the fore part of 
the tooth, and the other, which is less distinct, on die hinder 
part, hut this latter is wanting in the molars of the lower jaw: 
these smaller ridges appear to represent what \ have termed the 
band of the tooth, which in these animals is only developed in 
the parts mentioned. Besides the transverse ridges, is a longi¬ 
tudinal ridge, very nearly in the mesial lino of the tooth, but 
