ON THE OUTER REEF. 51 



Gothic minster ; cups, vases, and the classic 

 urns ; antlers of deer, of moose, of elk ; flowers, 

 vines, brakes, and mosses — all these forms came 

 before them as they drifted slowly along and 

 looked down upon this vast ocean garden. 



As Tom hurled his spear at a small parrot- 

 fish, Avhich darted under the boat, the weapon 

 landed in a large black mass about three feet in 

 diameter and concave on top, like a huge vase. 



" Hallo, what's this ? " he cried, hauling away 

 at the mass. 



'' It is a sponge," his father replied. " The 

 color represents the living part." 



" Why, are sponges animals, doctor ? " asked 

 Harry from the other boat. 



" Naturalists admit them to the ranks of ani- 

 mal life, though, of course, among the very low- 

 est forms," the doctor explained. " If you ex- 

 amine them closely in the water, you may see 

 a slight current over the pores and openings, 

 which shows that the necessary nourishment is 

 thus absorbed while it circulates through these 

 cavities. The common sponges, as we use them, 

 are but the skeletons." 



