CRINOIDEA. 677 



gorgon-headed,) (see Chart,) is remarkable for its five arms divid- 

 ing into pairs of branches, which terminate in curled filaments, 

 and form a sort of net work. So numerous are these branches, 

 it is said, they may number eight thousand in one individual. 



The STAR-FISH, Asterias, has almost innumerable perforations 

 through which the cupping-glass feet protrude, enabling the ani. 

 mal to crawl up a surface as smooth as glass, and also assisting 

 it to hold its prey. The rays are so much enlarged as to become, 

 on that account, less flexible, and not so well fitted for locomo- 

 tion, but for this the animal is compensated by numerous per- 

 forations. 



The SCUTELLATED STAR-FISH, A. scutellata, has an angular 

 body, the lobes or rays of which are short, not exceeding the 

 diameter of the disk ; other species have a body furnished with 

 elongated rays, whose diameter exceeds the diameter of the disk. 

 The genus Ophiura, (Gr. ophis, a serpent; owra, a tail,) in its 

 long, slender arms, shows a resemblance to the tail of a serpent, 

 (see Chart.) These arms are flexible; and by giving them a 

 waving motion, the animal is able to swim. A number of spe- 

 cies of Star-fish are found on our coast, some of which have 

 proved very destructive to the oyster beds. The Providence 

 (R. I.) Journal, in reference to some in that vicinity, says, "It is 

 impossible to estimate the injury that has been done by the Star- 

 fish ; probably not less than twenty thousand bushels of oysters 

 have been destroyed, and unless it disappears, oystermen will 

 hardly be willing to plant their beds." 



FOURTH ORDER. CRINOIDEA, (Gr. XQIVOV, krinon, a lily ; eftfoj, 

 eidos, form.) ENCRINITES. 



This order includes species by far the larger portion of which 

 are extinct, but which are found abundantly in limestone or the 

 lower rocks. In the fossil state, they are known by the name 

 of Encrinites, a name suggested by the stony stem, and a 

 crown of rays bending in sigmoid curves, like the Greek letter 

 sigma, (a.) resembling "the stalk and elegant bell-shaped blossom 

 of a liliaceous flower." The living species are very rare. The 

 form of the body is oval or cup-like, protecting the internal soft 

 parts, and composed of numerous plates. The arms are five or 

 more in number, simple or branched, with lateral jointed append- 

 ages, and situated around the upper margin of the body, the 

 mouth being placed between them. It is when the arms are 

 closed that some of the species assume a lily-like appearance. 

 (See Encrinus liUiformis, on the Chart.) The joints composing 



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