98 



LIFE, IX ITS LOWER FORM3. 



occasion to notice, — all present the same structure, which 

 is thus eminently characteristic of the class, — a transpa- 

 rent, hard, brittle, crystalline deposit, hollowed into num- 

 berless isolated cells. These cells are sometimes so nume- 

 rous that the solid matter is reduced to a series of slender 

 bridges and attenuated pillars, when, though the beauty 

 is much enhanced, the fragility is in proportion. 



It is interesting also to observe the flexibility which is 

 imparted to the long rays of the Brittle-star. Though 

 composed of rigid and fragile plates, a wonderful flexibility 

 is afforded to it by their number and arrangement ; and 

 whoever has watched, either by its native sea-shore, or in 

 the tiny mimic ocean which the marine aquarium furnishes, 

 one of these animals twining over the shells and stones 

 that lie on the bottom, as it pursues its rapid but devious 

 course, must have been struck with the precision and ease 

 with which these plaited organs, all bristling over with 

 points and spines, catch hold of projections, and drag the 

 body along, in much the same manner as a man would do 

 if reduced to a prone position, and if all his limbs were 

 arms. 



Perhaps our readers think we have made small progress 

 in our travels from the Feather-star to the Sea-urchin ; 

 still there is an advance ; and in our next chapter we hope 

 to shew that the journey is not so long as might be sup- 

 posed. 



