in Natural History, a genus of extraneous foetids, usually of about an inch in length, and made up of a number of round joints, which, when separate and loose, are called trochites: they are composed of the same kind of plated spar with the foetid shells of the echini, which is usually of a bluish-gray colour, and very bright where fresh broken; they are all situated from the centre to the circumference, and have a cavity in the middle.

The entrochi are found of all sizes, from that of a pin's head to a finger's length, and the thickness of one's middle finger; and are plainly of marine origin, having often tea-balls adhering to them. They seem to be the petrified arms of that singular species of the sea star-fish, called *stellaria arboreifrons*.