Fishes of the kind familiar to us in the present day, having the skeleton usually completely ossified and the scales horny.

Delicate fleshy organs of prehension or touch possessed by many of the lower animals.

The latest geological epoch, immediately preceding the establishment of the present order of things.

The windpipe or passage for the admission of air to the lungs.

Three-fingered, or composed of three movable parts attached to a common base.

A peculiar group of extinct crustaceans, somewhat resembling the woodlice in external form, and, like some of them, capable of rolling themselves up into a ball. Their remains are found only in the Palaeozoic rocks, and most abundantly in those of Silurian age.

Presenting three distinct forms.