226 THE FISHERIES OF THE UNITED STATES. 



Though so tough and tuberculous above, on the under side it is soft and almost -white in tint, except where 

 the strong spines along the edges of each raj- protect the soft parts between. In the very center of the disk is the 

 opening of the mouth. It contains no teeth, but is surrounded by an elastic tube and guarded by the hard edges 

 of the skoleton-plates which hera it in. From this center run live furrows, one down each of the arms. 



Throughout all this branch of the Eadiates, observes Professor Forbes, the reigning number is five. "Among 

 the lu'oblems proposed by that true-spirited but eccentric philosopher. Sir Thomas Browne, is one, 'Why, among 

 sea-stars, nature chiefly delighteth in five points'? and in his Garden of Ci/nis he observes: 'By the same number 

 (five) doth nature divide the circle of the sea-star, and in that order and number disposeth those elegant semicircles 

 or dental sockets and eggs in the sea hedge-hog '. Among the lower and the typical orders we find this number 

 regulating the number of parts. Every plate of the sea-urchin is built up of pentagonal particles. The skeletons 

 of the digestive, the aquiferous, and tegumentary systems, equally present the quinary arrangement; and even 

 the cartilaginous frame-work of the disk of every sucker is regulated by this mystic number." 



But this is a digression. To return : Each furrow is filled, with the exception of a narrow path down the middle, 

 with small fleshy tubes, terminating in a disk, which are so evidently its means of locomotion, that you at once call 

 them feet. This is true enough so far as their function is concerned, for Five-fingered Jack certainly does walk by 

 means of them; but entirely wrong anatomically, ^o Radiate has "feet" properly speaking. In order to see how 

 the little beast makes use of these hundreds of walkiug appendages we must dissect him. Having done this, it 

 appears, that» through the seive-like surface of the niadreporic body, on the back of the disk, enters a constant 

 current of pure sea-water. This is received into a system of circular canals, which branch out, on each side of 

 every ray, and send out through minute openings in the broad plates on the lower side of the arm's fibers, 

 which, when swelled full of water, appear as the rows of feet-tubes already mentioned. These feet-tubes are 

 called amiulacrw, the grooves along each side of the arm, where they spring and where they are sui)plied with 

 water from the main canal underneath, the amhulaeral grooves, while the plates themselves, and the whole concave 

 under-surface between the spiny processes bordering the rays, form the ambulaeral tract. 



Now, the starfish's body is always full of water; beside the large stream flowing in through the madi-eporic 

 body, a constant inflow seems to take place by absorption through the thousand minute water tubes that wreath 

 about each spine, notwithstanding no microscope has yet been able to detect any opening in them. This insures- 

 that the ambulacne shall always be full of water; but the creature can control these, and when he wishes to 

 take a step forward he places one, a dozen, or a score of these feet-tubes a little forward, and draws a slight 

 amount of water from each, which causes a contraction of their sucker-disks, and gives them a firm hold. ■ By a 

 reverse process he lets go with his other feet, and by main strength drags his body up as far as he can. This 

 operation frequently repeated would give a continuous movement to his body which is not ungraceful, as he dips 

 down into a hollow or bends himself slowly over some obstacle. His movements are very deliberate, and he 

 moves hardly as fast as the second-hand of a watch. It is to the fullness of this water-system that the animal 

 owes its plump appearance. Take him out of the sea and the water will pour out all over him, iu a fierce 

 perspiration, which soon leaves him flat and thin on your palm. I may as well say here, that any one can 

 handle them without fear ; the old idea that they were poisonous was a worthless superstition. 



In addition to this water-system, for locomotion, starfishes have a heart and system of blood-vessels. This 

 consists of two circular vessels, one round the intestine, and one round the gullet, or heart, intervening between 

 them. " There are no distinct respiratory organs, but the eurfaces of the viscera are abundantly sup])lied with 

 cilia, and doubtless subserve respiration ; the sea-water being freely admitted into the genei-al body-cavity by 

 means of numerous contractile ciliated tubes, which project from the dorsal surface of the body." (Nicholson.) 

 There is a nervous system, also, in this apparently immovable and insensible denizen of the deep. A gangliated 

 cord surrounds the mouth and sends filaments out along the center of each arm, to the little red speck discernible 

 at the tip, which is the eye. How much they can see with these eye-specks is doubtful ; but there seems uo doubt 

 that they can ijerceive obstructions iu their path, for they begin to get ready to mount them before actuallj' 

 striking against them. 



The mouth, as I have said, is a mere circidar opening, without teeth. The stomach is reached through a short 

 gullet, and of itself is not large, so that it is difficult to understand how the tremendous gluttony for which this 

 fellow is famous can be accommodated ; until we have cut him open, and find that, as a part of the stomach, there 

 extend loose yellow pouches far into each arm, which nearlj' fill up much of the interior of the rays. When no 

 great meal is to be eaten these pouches or cwca are not brought into use, but when occasion arises they can contain 

 a surprising quantity. On the floor of each arm, which wo have cut open, is seen the ambulaeral ridge, uj^m 

 either side of which are the vesi(;les that supply the foot tentacles, which may be filled or emiitied at the jdeasure 

 of their owner. Above these, occupying the most of the interior space toward the end of the ray, and also 

 appressed between the caeca and the ui)i)er surface toward the center, are the berry-like clusters or racemose masses 

 of the generative organs. 



Few persons, proliably, suspe(^t that in so low a grade of beings the sexes are divided, yet this appears to be 

 the case in the starfishes. According to Prof. Alexander Agassiz, the males and females of our common species 



