STAR-FISHES, SEA-URCHINS. ETC, 



351 



Pht:, b, N. LaoiarnirlJ f Hiu> J'trt 



STAR-FISH IN WATER 



If pulled to pieces, each of the fii'e arm', orjingersj luiU 

 groiu into a perject star-pih 



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, ci in-i-tin;_; ii-iially of a \-ariably patterned admi.Kture of crimson, pink, and white. 



An extreme contrast in contour to the sun-star is 

 presented bj- the so-called BiRU'S-FOOT species, in 

 which the body is pentagonal and so flattened out 

 as to somewhat resemble the foot of a duck. In 

 ^ ^ ' ^MUSCk ^'^^ CuSHlON-ST\RS the body, while pentagonal, is 



'^TArjrf* ^ " .J^Hfl^flBI comparatively thick. 



" ^^ • r--"- .IT^^Kh^^^ 'j-j-ig so-called Sxake-ARMED Sand-STARS and 



Brittle-stars constitute a section distinguished 

 from the preceding by the character of the arms, 

 which branch separate!}- from the central body, and 

 are composed of an innumerable series of calcareous 

 joints, which snap asunder under the slightest 

 provocation. The great majorit}' of the species are 

 provided with five simple arms onl\'. In an ex- 

 ceptional form, howe\'er, known as the Shetl.\ND 

 AR(;1's, 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 wTithing, 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 



W.l« by E. CoFiniW] 



\_St, Ltonardi 



STAR-FISH, OUT OF WATER, 

 TURNING OVER 



The iucker-tipped tubes 'with ivhich the star-fiih effects 

 locomotion are ivell skoivn in this photograph 



