THE STARFISHES. 



267 



flexible stalks, each terminating in a pair of pincers. These are opened and shut by special muscular 

 fibres, and are in a state of continual movement, twisting about, and snapping at minute things which 

 come in their way. They are known as "pedicellarise,"* but their precise functions are not very 

 clear. It has been suggested that they may perhaps act as scavengers, catching up particles of dirt 

 from the surface of the body, and casting it off into the surrounding water. 



The Starfishes are excessively voracious animals, feeding indifferently upon shell-fish, crabs, 

 anemones, worms, and all kinds of carrion. Oysters and other bivalves have but little chance against 

 them. The Starfish enfolds the shell with its 

 arms, and protrudes the lower portion of its 

 stomach through its mouth and between the 

 valves of the shell, until it can seize upon the 

 body of its unfortunate occupant. Little by 

 little the great stomach is pushed farther and 

 farther out of its own body and over that of 

 its prey, until at last, if the oyster be a large 

 one, the pouches are withdrawn from the rays, 

 and the Starfish is substantially turned inside 

 out. This work of destruction is sometimes 

 carried on by a number of Starfishes interlacing 

 their arms together, so as to form a ball, which 

 rolls about in the water with the clams, 

 oysters, or other shell-fish in the middle of it. 

 Starfishes are thus very dangerous enemies to 

 the cultivation of oysters. In some places they 

 are so abundant as entirely to prevent any 

 oysters growing at all. The damage done by 

 them on the coast of the United States, between 

 Cape Cod and Stateu Island, is estimated at 

 over 100,000 dollars yearly. They sometimes 

 invade the oyster-beds in enormous hordes, coming quite suddenly at intervals of a few years. 

 Such an invasion came to Providence River, Rhode Island. United States, about the year 1860, and 

 caused a loss to the oyster-growers of 150,000 dollars. At another locality 2,500 individuals were 

 speared on an oyster-bed in two days. 



When Starfishes were first discovered to be enemies to oyster culture the captured ones 

 were torn across and thrown back into the sea, though not to die ; for Starfishes, like all 

 Echinoderms, have a considerable power of reproducing lost parts, a single arm having been known to 

 grow up into a new Starfish. Consequently, instead of diminishing the pest, the above method of 

 procedure would tend to directly increase it, two or three new enemies being made out of every 

 captive. Now, however, the oystermen hand their captures over to the gardeners, by whom Starfishes 

 are much valued as manure. The common Crossfish (Asterias ruhens) is largely used for this purpose 

 on both sides of the English Channel, and also in the Eastern Counties. This species is also known as 

 Five-fingers, Five-fingered Jack, and the Devil's-fingers or the Devil's-hands, these latter names being 

 used upon some parts of the Irish coast, where a Starfish is looked upon with superstitious dread. 



(2) Ophiuroidea. The name of this class is derived from the three Greek words : ophis, snake, 

 our a, tail, and eidos, form, and refers to the external form of these creatures (Fig. 11). They have 

 longish serpent-like arms attached to a relatively small and usually rounded body or disc, to which the 

 viscera are confined. The top and sides of the disc generally bear plates or scales of various sizes ; 

 and they are often more or less covered with limestone granules, spinelets, or even with groups of 

 spines. The precise mode of arrangement of the plates on the top of the disc varies in different 

 species ; but five pairs of plates, known as the " radial shields " (Fig. 11, rs), are always present, though 

 not always visible. Each pair corresponds to the base of one of the arms or rays, one plate lying on 

 either side of the ray, not far from the edge of the disc. This is usually, but not always, notched for 



* Latin, diminutive of pedicellus, a louse. 



Fig. 11. COMMON BKITTLE-STAK (Oyhiothris fmgllis). 

 Natural size. rs t radial shields. 



