ECHINODE EMATA 



71 



inflexible legs, upon which the Echinus rolls itself from 

 place to place, or by their assistance it can bury itself in 

 the sand mth the greatest facility. But these wonderfully- 

 constructed animals are by no means confined to this mode 

 of progression; for imj^ossible 

 as it might seem from their 

 outward a2:)pearance, they are 

 able to climb rocks in search 

 of food, and thus obtain the 

 corallines and shell-fish upon 

 which they princij)ally feed. 

 To enable them to eflect this, 

 their shell is perforated with 

 ten rows of small orifices, ex- 

 tending from one i^ole to the 

 other, like the lines of longi- 

 tude upon a globe, through 

 which long suckers issue similar 

 in structm-e to those of the star- 

 fish, but long enough to extend beyond the points of the 

 S23ines; so that, by their assistance, the Sea-Urchin not 

 only scales the cliff, but creeps along pendent fi-om the 

 roofs of submarine caverns. 



Fig. 47.— greex-pea urchin. 



Fig. 48.— figure of sucker of 



The number of these suckers is very great : in a mode- 

 rate-sized Urchin, Professor Forbes reckoned sixty-two 

 rows of pores in each of the ten bands ; as there are three 

 paii^s of pores in each row, their number multiplied by 

 six and again by ten would give three thousand seven 



