We will now turn for a short space to the lower divisions of the animal kingdom. The Echinodermata (starfishes, sea-urchins, etc. ) are furnished with remarkable organs, called pedicellariae, which consist, when well developed, of a tridactyle forceps⁠—that is, of one formed of three serrated arms, neatly fitting together and placed on the summit of a flexible stem, moved by muscles. These forceps can seize firmly hold of any object; and Alexander Agassiz has seen an Echinus or sea-urchin rapidly passing particles of excrement from forceps to forceps down certain lines of its body, in order that its shell should not be fouled. But there is no doubt that besides removing dirt of all kinds, they subserve other functions; and one of these apparently is defence.