384 



THE NATURE BOOK 



under loose, flattish stones, may be found 

 the plump little Cushion Star-fish {Asterina 

 gibbosa), which has no definite arms, 

 but only five projecting corners. 



To find the dainty little Sand and 

 Brittle Star-fishes, we must seek along 

 the stretches of sand at low-tide mark, 

 and in the clear rock pools. Graceful in 

 shape, dehcately tinted, extremely fragile, 

 these little Star-fishes must be handled 



A GROUP OF SEA URCHINS. 



with great care, or numerous arms will be 

 missing long ere the httle creatures are 

 brought back from the afternoon ramble. 

 One of the treasures to be found amongst 

 the rock pools is the beautiful Rosy 

 Feather Star-fish [Antedon rosacea), with 

 its graceful, deep red, plume-like rays or 

 arms. It is a most intensely interesting 

 as well as a beautiful creature, on account 

 of its somewhat remarkable hfe-history. 

 The Rosy Feather Star -fish starts life as 

 a little oval, comparatively active, free- 

 swimming creature : a little later it be- 

 comes attached to a rock, when it has a 

 slender stalk, at the top of which the 

 plume-hke rays develop, so that the Rosy 

 Feather Star now looks hke a graceful, 

 rayed flower — a sea-lily. After a time 

 the beautiful flower-head breaks away 

 from its slender stem and becomes an 

 adult Feather Star. It is the stalked 

 stage of the Rosy Feather Star-fish that 

 is so interesting, for it represents a very 

 ancient type of creature, which under the 



name of Stone Lily {Encrenite). is common 

 as a fossil in the limestone rocks. Indeed, 

 in past geological ages these Stone Lilies 

 must have been very abundant in the 

 seas which covered what is to-day dry 

 land. 



While scrambling over the rocks and 

 amongst the pools, seeking the Rosy 

 Feather Star-fish, we are fairly certain 

 to come upon one or two specimens 

 of the common Sea Urchin 

 {Echinus miliaris), the typi- 

 cal representative of a very 

 interesting group of animals 

 that are close cousins to 

 the Star-fishes. At first it 

 is a little difficult to reahse 

 that this prickly little crea- 

 ture, with its hard, shelly 

 test or body plates, is a 

 near relation of the Star- 

 fish. If we place a living 

 specimen in a glass vessel 

 of sea-water, however, we 

 shall be better able to re- 

 cognise the relationship, for 

 we shall there see that 

 amongst the forest of spines 

 with which the Sea Urchin 

 is clothed, there are numer- 

 ous suckers or tube feet 

 arranged in a similar man- 

 ner to those which run down the centre 

 of the arms of the Star-fish ; and it 

 is by means of these tube feet that 

 the Sea LTrchin is able to move about, 

 and in captivity to crawl up the glass 

 side of the aquarium. If we carefully re- 

 move all the spines from the test or 

 shell of a dead Sea Urchin, we shall be 

 able to see what a wonderful and beauti- 

 ful object the test is, and how it is per- 

 forated at regular intervals by holes for 

 the protrusion of the tube feet. 



A Crab hastily scuttling across the 

 sands, or sitting back and holding out 

 its powerful claws in an attitude of comical 

 defiance, is one of the most familiar 

 sights of the shore. Besides these com- 

 mon shore Crabs, there are many others 

 that may be discovered during one's ramble 

 along the sands and amongst the rock 

 ])ools. In the latter situation we are 

 almost certain to make the acquaintance 

 of some of the curious, slenderly-built 

 Spider Crabs, and the queer - looking 



