ORDER IV. 
TDN bene aliges 
Teeth simple, or none at all ; always wanting in the anterior part of the jaws. 
The ELdentata of modern authors correspond to the Bruta of Linneus, which embraced, how- 
ever, several genera to which the diagnosis, as above given, does not apply. Setting aside these, 
(Trichechus, Elephas, and Monodon,) we have left, as constituting the Bruta of Linnezus, 
Bradypus, Myrmecophaga, Manis, and Dasypus, to which more recent authors have added - 
Choloepus, Chlamydophorus, Orycteropus, &c., together with Echidna and Ornithorhyncus. 
These constitute the principal living genera of Hdentata, but there are several extinct ones to 
be added to the list, as Megalonyx, Megatherium, Mylodon, &c. 
The genera of Zdentata, though few in number, are yet so different from each other as to 
admit of being arranged in three families, Bradypoda, Effodienta, and Biclaviculata.! These 
may be briefly characterized as follows: 
I. Brapypopa.—With canine and molar teeth. Malar bone with an additional inferior process. Stomach divided. Ante- 
rior limbs very long. Mammae, pectoral. Tail very short, or wanting. Fur dry and coarse. 
Of this family, embracing the sloths proper, no representatives are found in North America. 
Fam. 2. Erroprentia.—Teeth uniform, or none. Malar bone simple, or wanting. Muzzle elongated. Limbs short, stout ; 
the hinder ones longest. Stomach simple. 
This family, embracing the armadillos as the most prominent form, has one living repre- 
sentative in North America, Dasypus novem-cinctus, found abundantly on the lower Rio Grande of 
Texas. 
Fam. 3. Bictayicutara, or Monotremata.—Clavicles double. Mammal papillae, wanting, Well developed marsupia 
bones. Cloaca simple. Males provided with spurs to the eet. 
This family embraces two very extraordinary forms of animal life, the Hchidna and the Orni- 
thorhynchus, both natives of Australia. 
It is proper to state that high authority, such as that of Waterhouse and others, place the 
Monotremata at the end of the Marsupialia. 
There is a very striking contrast between the H/ffodientia, as characterized above, and the 
Bradypoda, 
In the latter, the structure of the animal is adapted to a residence upon trees, and it is 
only exceptionally that the sloths are found on the ground. In the armadillos, on the other 
hand, the solid covering, and the long fossorial claws, indicate a terrestrial habitat, and that 
rather beneath than above the surface. The food of the two groups is equally diverse ; that of 
the sloths consisting of the leaves and twigs of trees, while the armadillos seem created espe- 
cially to keep in check the myriad insects of tropical regions, and especially the ants, the most 
abundant of all. 
‘Wagner, Suppl. Schreber, IV, 130. 
