RopENTIA. 269 
Dr. Kellaart ee that at an ssh age this animal has as many as 32 
teeth, viz. inc. - and molars 5—5, but when adult there are only 14, as 
mentioned above. The molars, pbk eee to Dr. Murie, succeed each 
other, the fore ones dropping out, and others from behind taking their 
places. It feeds on fucus and other seaweeds, and the flesh is con- 
sidered good eating, and not unlike veal or, some say, pork. They are 
lethargic in disposition, and in those countries where they have been 
unmolested they are so fearless of man as to allow themselves to be 
handled—a confidence somewhat betrayed by the natives, who on such 
occasions manage to abstract the fattest calves, which are considered a 
delicacy. 
ORDER RODENTIA, 
THE GNAWERS. 
Tuis order, Giires of Linnzus and his followers, is composed of 
animals, chiefly of small size, which differ from all others by the 
peculiarity of their teeth. No one, even though he be most ignorant 
of comparative anatomy, could mistake the rat or rabbit-like skull of a 
rodent for that of any other creature. The peculiar pincer-like form 
of the jaws, with their curved chisel-shaped teeth in front, mark the 
order at a glance. ‘There is no complexity in their dentition. There 
are the cutters or incisors, and the grinders ; and of the cutters there are 
never more than two in each jaw, that is to say efficient and visible 
teeth, for there are in some species rudimentary incisors, especially in 
the young, but these either disappear or take no partin work. Between 
the grinders and incisors are toothless gaps. The formation and growth 
of the teeth are peculiar ; and it is strange that the gigantic elephant 
should be the nearest approach to these small creatures in this respect. 
The teeth—in most cases the grinders, but always the incisors—grow 
continuously from a persistent pulp, and therefore loss from attrition 
is kept constantly supplied by growth from behind. The incisors are 
planted in a socket which is the segment of a circle. These segments 
are not equal in both jaws. The lower one is a small segment of a 
large circle, the upper one is the reverse, being a larger segment of a 
smaller circle. The angle at which they meet is always thesame. Some 
curious malformations are occasionally found which illustrate the growth 
of these teeth. Should by any chance, accident or design, one of these 
incisors get diverted from its proper angle and not meet with the friction 
which is necessary to keep it in its normal condition, it goes on growing 
and growing, following its natural curve till it forms a ring, or by penetra- 
