378 RADIATA. 



dually as with difficulty to be separated, are, as might 

 be supposed, very diverse in their structure and degree 

 of perfection. In the very highest, however, the 

 nervous matter is not collected into knots or ganglia, 

 connected by continuous cords, and therefore their 

 senses, except that of touch, are feeble, if not 

 entirely wanting ; there is no organ answering to a 

 heart, and no circulation of anything like blood; 

 and generally no distinction of sex: while in the 

 lowest, we see nothing but a simple mass of thin 

 jelly, alike in every part, without any organs that we 

 can discover, and without any tokens of life, save 

 in alternate contraction and dilatation. Yet some of 

 these animals, and those almost the lowest in the 

 scale, have been employed by God, to perform 

 mighty works in our world, such as erecting barriers 

 against the fury of the ocean, and raising from its 

 fathomless depths spacious islands for the habitation 

 of man. 



