46 



FIRST LESSONS IN ZOOLOGY. 



to which the spines are attached. The sand-cake urchin 

 (Fig. 45) is very flat, with minute spines. 



On placing an Echinus in sea-water the movements of 

 the animal, especially its mode of drawing itself along by 



FIG. 46. Echinus on its back. 



its numerous long suckers, and how it covers itself by 

 drawing together bits of sea-weed and gravel, may be ob- 

 served. 



Of course the sea-urchin is a heavier, clumsier creature 

 than the starfish, and when turned over on its back feeble 



FlG. 47. Echinus extending its suckers on beginning to right Itself. 



ones cannot right themselves; but a fresh, vigorous urchin 



can turn itself over in the manner indicated by Figs. 40-49. 



Sea-urchins live in nooks and crannies in the rocks, away 



from the wash of the waves, as they are clumsy creatures. 



