sensitive organs of touch, or some analogous sense, which inform the animal of the presence, and perhaps of the nature, of objects within reach. At the same time I remarked that the outer foot-jaws (pedipalps) were employed alternately in making casts, being thrown out deliberately, but without intermission, and drawn in, exactly in the manner of the fringed hand of a Barnacle, of which both the organ and the action strongly reminded me. I looked at this more closely with the aid of a lens: each foot-jaw formed a perfect spoon of hairs, which at every cast expanded, and partly closed. That you may understand this better I must say, that the foot-jaw resembles a sickle in form, being composed of five joints, of which the last four are curved like the blade of that implement. Each of these joints is set along its inner edge with a row of parallel bristles, of which those of the last joint arch out in a semi-circle, continuing the curve of the limb; the rest of the bristles are curved parallel or concentrical with these, but diminish in length as they recede downwards. It will be seen therefore that when the joints of the foot-jaw are thrown out, approaching to a straight line, the curved hairs are made to diverge; but as the cast is made, they resume their parallelism, and sweep in, as with a net, the atoms of the embraced water.
The microscope revealed to me a still higher perfection in this admirable contrivance. I then saw that every individual bristle is set on each side with a row of short stiff hairs, projecting nearly at right angles to its length; these hairs meeting point to point those of the next bristle, and so on in succes-
