60S THE WONDERS OF GEOLOGY. Lect. VI. 



moving in different directions, but generally all converging 

 towards the orifice or mouth, which is situated not in the 

 centre of the crown of cilia, but between the two rows of 

 these organs, which exist consecutive to one another. The 

 attention is no sooner drawn to this interesting spectacle, 

 than presently the bodies of the animals, which were before 

 quite transparent, become dotted w T ith distinctly circum- 

 scribed spots, of a dark blue colour, exactly corresponding 

 to that of the moving particles of indigo. In some species, 

 particularly in those which are provided with an annular 

 contraction or neck, separating the head from the body, the 

 molecules of indigo can be traced in a continuous line in 

 their progress from the mouth to the internal cavities. 



The animalcules termed Monads, may be considered as 

 the lowest term of animal organization recognisable by 

 man, being only from the 1,200th to the 24,000th part 

 of an inch in diameter, and the powers of the micro- 

 scope extend no farther ; yet it is impossible to doubt 

 that there are myriads of living forms more infinitesimal, 

 some of which serve as food to these miniatures of 

 life.* 



13. Nature of Coral Zoophytes.— In the larger and 

 free masses of Flustra, the decomposition of the animal 

 substance after death is very manifest. This specimen of 

 Flustra foliacea, which was dredged up twenty miles 

 SS.W. of Brighton, in water eighteen fathoms deep, is a 

 fine example of this brittle species ; when first in my pos- 

 session it was highly offensive from the emanations evolved 



* " The size of the ultimate particles of matter must be small in the 

 extreme. Organized beings, possessing life and all its functions, have 

 been discovered so small that a million of them would occupy less 

 space than a grain of sand. The malleability of gold — the perfume of 

 musk— the odour of flowers — and many other instances might be given 

 of the excessive minuteness of the atoms of matter : yet, from a variety 

 of circumstances, it may be inferred that, matter is not infinitely 

 divisible." — Mrs. Somerville, p. 1~.">. 



