AND STAR-FISH. 169 



into each arm in the true star-fishes, thus forming 

 another distinctive feature. In the " Brittle-stars " 

 (Ophiura) it is confined to the body, and does not 

 enter the arms at all. The nervous system consists 

 of a ganglionated ring running round the mouth, 

 and sending branches up each arm. The "Sun- 

 star " (Solaster pa/pposa) is another common British 

 species, which may be readily known by its twelve 

 arms or rays. They have only two rows of suckers 

 in each furrow, but, like the Urasters, they are dis- 

 tinguished by having the back rounded or arched, 

 the Asteroids being flat. The beauty of their skin 

 is also noticeable, being usually of a red or a reddish- 

 purple colour. The Solaster is abundant along all 

 the coasts of Western Europe. There is a singular 

 arrangement at the ends of each arm, in the shape 

 of tentacular processes, and a so-called eye-speck, of 

 a scarlet colour, which is protected by rows of spiny 

 fans. So voracious is the sun-star, that he does not 

 hesitate to devour the sea-urchin, spines and shell 

 and all ! 



We now come to another familiar group of star- 

 fish, whose peculiar custom of throwing off their 

 arms in pieces when alarmed has earned for them 

 the deserved name of "Brittle-star." It is of this 

 species that Professor Edward Forbes speaks as 

 follows: "The common Brittle-star often congre- 

 gates in great numbers on the edge of scallop banks, 

 and I have seen a large dredge come up completely 

 filled with them : a most curious sight ; for when 



