STAR-FISHES, SEA-URCHINS, ETC. 



749 



o b, K. Laxarniif] [Nrw Tirl 



STAR-FISH IN WATER 



If pulled to pieces, each of the five arms, or Jjngers, 'will 

 groiv into a perfect star-fish 



to within comparatively recent years the so-called 



MEDUSA'S-HEAD 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- 

 shaped 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 STAR-FISH, 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 admixture of crimson, pink, 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 

 BRITTLE-STARS constitute a section distinguished 

 from the preceding by the character of the arms, 

 which branch separately from the central body, and 

 arc 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 simple 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 Medusa'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 



Phtto by E. Connoltf] 



[S/. Leonardi 



STAR-FISH, OUT OF WATER, 

 TURNING OVER 



The sucker-tipped tubes 'with 'which the star-fish effects 

 locomotion are 'well shown in this photograph 



