THE OYSTER-INDUSTRY. 225 



of these feasts accumulate mouuds or ridges hundreds of yards long and perhaps forty feet high. When the white 

 man comes along, he discovers the largest trees and most luxuriant undergrowth upon these mounds of shells. 

 Recognizing the excellence of the soil, it is there he places his house and plants his farm. The old oyster bar is 

 an island with a name on the maps. 



Now, the formation of keys just in this way has long been going on, and clusters of them abound all the way 

 from Apalachicola to Key West. A group of islands, near such a coast as Florida's, acts like the interlacing 

 roots of a single mangrove key; the currents are stopped, tides slackened, shell-debris, drifted matter, and sand 

 deposited, and great shoals, mudflats, and sand-bars result. Given such an archipelagic condition, a straight 

 sand-bar, or outer beach, is a natural result, and this, once it is formed, contributes still more to the shoaling of 

 the channels inside, until they eventually become largely obliterated, and many of the islands join together and 

 finally unite with the mainland. 



But, as I have said, this is wholly the work of animal life. Not until the oysters and their neighbors have 

 really formed a "key", do the mangroves, with their train of aids, take up the work; and not until this has long 

 proceeded does the drifting of sediment down the rivers, or the washing up of bottom-sand by the outer waves, 

 increase the bulk of the islands that soon add their well-prepared areas to the general coast. 



V. EATALITIES TO WHICH THE OYSTER IS SUBJECT. 



61. LIVING ENEMIES OF THE OYSTER. 



The starfish. — No creatures are so dangerous enemies of oysters, either in their wild state or when 

 transplanted, as the members of the spiny-skinned tribe which naturalists term Echinoderms. This tribe contains 

 many members, but the one that concerns us as oyster-growers is the starfish. 



The starfish passes under various names among fishermen and oystermen. In England he is known most 

 frequently as the "crossfish", "sun-star", and "sea-star". In this country the name most often heard, is "five- 

 fingers" north of Cape Cod, and southward of there "starfish", "sea-star", or simply "star", to which it is 

 abbreviated in the vicinity of New York. 



None of these names, however, distinguish between the various species, except in the case of the "basket-fish" 

 of Massachusetts bay, which is sufficiently different from the ordinary five-fingers to attract everybody's attention ; 

 and the smaller varieties are often mistaken for the young of a larger sort. While this is unfortunate ignorance, 

 it practically does not matter to the oysterman, since all the different members of the family are alike enemies, to 

 the full extent of their individual powers and opportunities. 



The common name of the animal well describes its general form. "As there are stars in the sky so are there 

 stars in the sea," remarked old John Henry Link, a century and more ago. From a central disk of small dimensions 

 radiate five pointed arms, composed of a tough substance unlike anything else that I remember anywhere in the 

 animal kingdom. " When it i.? warm in one's hand," wrote Josselyn, that quaintest of America's advertisers, in his 

 Neic EnglaiuVs Earities, IG, "you may perceive a stiff motion, turning down one point and thrusting up another." 

 This was all right, but he adopted an error when he added : " It is taken to be poysonous." 



Examining the starfish more closely, you perceive that it has an upper and a lower side, essentially different. 

 The upper side, or back, presents a rough surface of a greenish, brownish, or reddish-green hue, which, when it is 

 dried, turns to a yellowish-brown. This is the leathery membrane covering the skeleton of the animal, which 

 consists of small limestone plates united together at their edges by a sort of cartilage, so that they can move in a 

 slight degree. This forms the frame-work of the arm, and acts as a chain-armor to encircle and protect all the 

 soft parts within. Underneath, on the lower side of the starfish, this frame-work terminates in two series of larger 

 plates, which are braced against one another like rafters, and sustain the whole structure by a sort of arch. This 

 armor is sufficiently flexible to allow the starfish to bend himself clumsily over or around anything he is likely to 

 wish to climb upon or grasp. 



Scattered everywhere upon the upper side are a large number of blunt, short spines, which seem to have no 

 special arrangement, and are longest and thickest at the edges of the rays, and upon the plates bordering the 

 lower side of each ray. Each one of these spines swells at its base, where are fixed, in a wreath, several curious 

 little appendages called pedkellariw, whose odd forms and movements can only be understood underneath a 

 powerful microscope, on account of their diminutive size. They consist of a little pedicel which waves about, 

 bearing upon its top a pair of (for it) huge toothed jaws, like the claw of a lobster, which waves about in a very 

 threatening manner. Now and then it happens that some little particle of food or sea-weed will accidentally get 

 caught by these valiant guardsmen of the spine, that towers up iu their midst ; but this to annoy rather than 

 gi-atify them, and their functions are not yet explained. They occur in some form or other in all echinoderms, yet 

 seem to contribute no service whatever to the animal. Outside of them, forming a second circle about each spine, is 

 a set of water-tubes, whose functions will be explained presently. Near the center of the disk, on the back, notice the 

 madreporic hody, a small, smooth protuberance, filled with openings, like a sprinkler, and then turn the starfish over. 

 15 o 



