48 INTRODUCTION 10 ZOOLOOY. 



many oeciisious, seen a dredge come up half filled Avitli a 

 spine-covcred species (OpJtiura rosiila) everywhere abundant 

 round the coast, and can bear testimony to the accuracy of 

 Professor Forbes' description : — " Of all om-native Brittle-star^, 

 this is the most common and the most variable. It is also 

 one of the handsomest, presenting every variety of variega- 

 tion, and the most splendid displays of vivid hues arranged 

 in beautiful patterns. Not often do we find two specimens 

 coloured alike. It varies also in the length of the ray-spines, 

 the spiuousness of the disc, and the relative proportions of 

 rays and disc ; and in some places it grows to a much greater 

 size than in others. It is the most brittle of all Brittle-stars, 

 separating itself into pieces with wonderful quickness and 

 ease. Touch it, and it flings away an arm ; hold it, and in a 

 moment not an arm remains attached to the body." 



The word a.'iter means a star, and the term Asteriado! is 

 applied to the third family; that to which the true Star- 

 fishes, or those which are typical of the class, belong. If we 

 take from our cabinets a dried specimen of the common 

 Cross-fish, or " Five-fingers," we find the mouth on the lower 

 surface of the central disc, and five rays, with deep grooves 

 throughout their entire length. Each groove contains a 

 multitude of small orifices, through each of which, when alive, 

 tlie anhnal could protnide a tubular organ, capable of adhering 

 to the surfoce of any body to which it was applied. By such 

 means, its prey can with ease be overcome, dragged into the 

 oral orifice in the centre of the rays, and devoured. 



But these suckers, which render the Cross-fish so formidable 

 an assailant, are not only organs of prehension — they are also 

 organs of locomotion. To appreciate them aright, they must 

 be seen in action; for words alone will not convey an adequate 

 idea of the singularity and beauty of their mechanism. On 

 this subject, we prefer the words of Professor Rymer Jones 

 to any which we ourselves could employ* : — " Let any of our 

 readers, when opportunity offers, pick up from the beach one 

 of these animals, the common Star-fish of our coast, which, 

 as it lies upon the sand, left by the retiring waves, appears 

 so incapalje of movement, so utterly helpless and inanimate; 

 let him place it in a large glass jar, filled with its native 

 clement, and watch the admirable spectacle ^\liich it then 



' Outline of tho Animal Kingdom, p. 141. 



