OR, PLAIN TEACHING. 359 



the shore they may be seen 

 springing in thousands from 

 among the pebbles. 



Paley in his "Natural Theology" relates a 

 circumstance which will give some idea of the 

 shoals of these little animals. " Walking," he 

 says, " by the sea side, in a calm evening, upon 

 a sandy shore and with an ebbing tide, I have 

 frequently remarked the appearance of a dark 

 cloud, or rather very thick mist, hanging over 

 the edge of the water, to the height perhaps of 

 half a yard, stretching along the coast as far as 

 the eye could reach, and always retiring with 

 the water. When this cloud came to be exa- 

 mined, it proved to be nothing else than so 

 much space filled with shrimp-like creatures in 

 the act of bounding into the air from the shallow 

 margin of the water or the wet sand." 



Corallines, or zoophytes, 14, are 

 compound animals that live upon 

 one general structure, frequently 

 assuming a plant-like form. 

 Those most commonly known 

 are moss corals, so called from 

 their moss-like appearance. In 

 some instances they grow upon 

 sea weeds, completely covering 

 11 



1180. 



their surfaces with small cells, 

 resembling honeycomb. These 

 possess a higher organisation 

 than the simpler polyps, 15, 

 many of which so closely re- 

 semble delicate sea weeds, that 

 they have frequently been mis- 



taken for them. Viewed under 

 the microscope these are highly 

 interesting objects ; specimens 

 enclosed in vials with a little 



salt water may be favourably 

 observed, the animals coming 

 forth from their concealment, 

 and displaying their beautiful 

 and delicate forms. 



The sea urchin, or egg urchin, 

 16, is one of a curious genus of 

 oval or egg-shaped animals, most 



16 



1182. 



of them covered with spines, 

 connected with the outer shell, 

 or skin, by very strong liga- 

 ments. The mouths of these 



