Fowls with long legs and mostly diminished toes—Bustard, Cassowary, and Ostrich.
These Birds have mostly such shortened wings, that they cannot elevate themselves from the earth. In the Cassowary we find, in place of the primary feathers upon the wings, five barbless quills like so many claws. The Ostrich has a pelvis closed in front like the Mammalia. It has not incorrectly been compared with the Camel, since the Ruminant animals in general have many resemblances in common with Birds, especially in the development of the horny substance, which obviously agrees with the feathers.
Thirteenth Class.
Aistheseozoa, Opthalmozoa—Thricozoa.
3560. All the senses perfect, five digits; the face covered with skin and flesh, the body with hairs; mammæ present.
3561. The Thricozoa combine in themselves all the animal classes, and indeed, so far as the development by grades makes no distinction, in equal proportion.
The differences are in no class therefore so numerous and so strongly pronounced as in this; and yet one is in more doubt almost concerning the rank of the families than in the former classes. It turns out, therefore, that they are not treated according to sound or solid principles, but that these, after the manner in which Natural History is still prosecuted, are despised.
Upon viewing superficially the groups of Thricozoa, it is certainly difficult to determine, which are the lowest families, although the uppermost ones are very well known; so that here matters are the reverse of what they were in Plants. In the case of Birds the empirical inquirer into nature knows neither which are the upper, nor which the lower groups; while in the Reptiles and Fishes he fares still worse.
It is pretty generally conceded that the Whales are the lowest in point of rank, because their posterior feet are wanting, and in this they certainly do depart the most from the usual or normal form of the Thricozoa; yet still it is just these animals which form the proper starting-point for the present class. Even the empirical naturalists here begin to employ physio-philosophical language, and designate these animals by the title of Fish-like Thricozoa. But, if they repeat the Fishes, then there must be Thricozoa, which stand or rank below them, and pass parallel to the Dermatozoa. Which these latter are, is not indeed to be declared until the other groups have been separated and brought into their proper station or place.
If once there are Ichthyoidal there must also be Herpetoidal or Reptile-like Thricozoa. Now, if the Whales correspond to the former, then the serial arrangement of the latter kinds is readily enough decided. To the Whales no other animals admit of being annexed but the Swine-like genera, such as the Hippopotamus, Pig, and Elephant, which, through their muscular mass, almost naked skin, and residence in marshy situations, agree very closely with the Reptilia.