Star^fishes, Sea-urchins, etc. 



749 



If pulled to jiieces, 



STAIl-FISH IS WATER. 



;Lch of the fivo arms, or fingers, ^vill grow into 

 ;i perfect star-fish. 



to within comparatively recent years the so-called 

 ]\lEDUSA'8-nEAD LiLY was, indeed, regarded as 

 the only living representative of the group. This 

 species has a pentagonal jointed foot-stalk that 

 may be 3 feet long, with five slender appendages 

 developed in whorls at short sub-equal distances 

 throughout its length. From the shallow cup- 

 sha]ied body at the apex of the stalk a tassel-like 

 bundle of arms is developed, all of these being 

 produced by repeated bifurcation from one of 

 the five equivalent basal stem-joints. Dredging 

 expeditions have within the last quarter of a 

 century revealed the existence of a considerable 

 number of previously unknown species of stone- 

 lilies in the abysses of the ocean, a depth of no 

 less than 3,200 fathoms representing the habitat 

 of one such type. 



The Star-fish group is represented by the 

 Common Five-fingers, or Cross-fish, as it is 

 sometimes called, and includes a very numerous 

 assemblage of species of varying size and shape 

 and colour. The British seas alone yield some 

 twenty forms. Among the more notable of these 

 is the Sun Stak-fisu, which, departing from the 



rule of possessing five arms only, has twelve or more, its contour, from which it derives its 



name, somewhat resembling that of a symbolic sun. The colours of this species are particularly 



brilliant, consisting usually of a variably patterned admixtm'e of crimson, ])ink, and white. 



An extreme contrast in contour to the sun-star is 



presented by the so-called Bird's-foot species, in 



which the body is pentagonal and so flattened out 



as to somewhat resemble the foot of a duck. In 



the Cushion-stars the body, while pentagonal, is 



comparatively thick. 



The so-called Snake-armed Sand-stars and 



Briitle-stars constitute a section distinguished 



from the preceding by the character of the arms, 



which branch separately from the central body, and 



are composed of an innumerable series of calcareous 



joints, which snap asunder under the slightest 



provocation. The great majority of the species are 



provided with five simp)le arms only. In an ex- 

 ceptional form, however, known as the Shetland 



Argus, and its allies, these five arms, while simple 



at their base, bifurcate repeatedly and in geometrical 



progression to such an extent as to form in life 



a complex network of writhing, snake-like tendrils, 



that has been appropriately likened to a jMedusa's 



head. It has been calculated that there are no 



less than 80,000 terminal arm-subdivisions in adult 



examples of this species. 



Among the Sea-urchin Tribe there are 



many notable departures from the typical form 



Photo hij E. ConnoUI.] [&t. Leonards. 



STAE-FISH, OUT OP WATER, TUENIKG OVER. 



The sucker-tiltped tubes with -which the sttir-fish etfects loco- 

 motion are uell shown in this photograph. 



