The lower or actinal surface of each arm is deeply channeled and perforated by many holes or pores, through which the little ambulacra or water-feet are thrust. These serve as organs of locomotion, of respiration and of perception. These water-feet form a part of the wonderful water-vascular system, which consists of a madreporic body, or sieve-like organ, opening on the dorsal or actinal surface and situated between two rays. It opens into a tube called the stone canal, which enters a circular vessel called the circum oral water tube, surrounding the mouth, and a long radial canal, to which the water-feet are attached, opens from this tube and extends along the inner surface of each ray. The water enters the madreporic body, circulates through the stone canal, the circular and radial tubes, and finds its exit through the ambulacra. The water system is directed and controlled by a set of nerves, extending from a ring of nerve matter surrounding the mouth. The true vascular or blood system consists of a heart or hæmal canal, which runs parallel with the stone canal from the madreporic body to the oral water tube. A set of circular and radial vessels supplies every part of the animal with the vital fluid. The digestive system is simple and consists of a mouth, a stomach, which is large and sends a lobe into the base of each arm, and an intestine of greater or lesser length, ending in a small anal opening on the dorsal surface. The cœca or liver consists of two long, tree-like masses, nearly filling each ray and connecting with the stomach by a short duct. Starfishes are very destructive to the oyster beds along the Atlantic coast of the United States, thousands of bushels of oysters being destroyed in a few days by them. The little starfishes attack the young oysters and as the former increase in size they move about in vast numbers, resembling in this respect the grasshoppers and locusts of the west and being fully as destructive. In a paper in a Bulletin of the United States Fish Commission, by Henry C. Rowe, it is stated that in 1882 $90,000 worth of oysters were destroyed in six months and $9,000 were spent in the same period in catching the starfishes. The method of catching these animals is interesting. Devices called “tangles” and “mops” are used. These consist of a heavy iron frame, to which about twenty small ropes, ending in a large bunch of cotton waste, are fastened. These “mops” are drawn over the oyster beds and the starfishes become entangled in the waste and are then drawn on board the vessel. As many as 1,500 starfish have been taken from a single “mop.”