222 



ANIMALS OF LAND AND SEA 



One of the smaller earth-worms, nearly world-wide in its 

 occurrence near the coasts and found with us as far north as 

 Washington, secretes a luminous mucus when disturbed which 

 gives off a greenish yellow light. 



Under logs and stones you sometimes find very slender centi- 



4- 



^ -'k-- 



^^^ 



Figs. 665-668. Ilydroids. 

 For explanations of the figures see p. xxxii. 



pedes, quite different from the common stouter ones. At cer- 

 tain times these slender centipedes are brightly luminous, the 

 light spreading out over the whole under surface of the animal. 

 If one is taken up the luminous secretion comes off upon the 

 hand as in the case of the luminous earth-worms. 



In some of these the upper side is also luminous, the head 

 lighting up with a bright greenish light which spreads back- 



