i8 



SPONGES. 



apertures on the side of the sponge fully into view, I beheld, for 

 the first time, the splendid spectacle of the living fountain vomit- 

 ing forth from a circular cavity an impetuous torrent of liquid 

 matter, and hurling along, in rapid succession, opaque masses, 

 which it strewed everywhere around. The beauty and novelty 

 of such a scene in the animal kingdom long arrested my atten- 

 tion ; but after twenty-five minutes of constant observation, I 

 was obliged to withdraw my eye from fatigue, without having 

 seen the torrent for one instant change its direction, or diminish 

 in the slightest degree the rapidity of its course. I continued to 

 watch the same orifice at short intervals for five hours, sometimes 

 observing it for a quarter of an hour at a time ; but still the 

 stream rolled on with a constant and equal velocity." 



The sponges perpetuate 

 their race by a very curious 

 mode of increase. At stated 

 periods there project from the 

 interior of the larger canals, 

 that traverse their substance 

 in all directions, minute oval 

 masses of jelly, which grow, 

 till at length they are detached 

 and driven out by the issuing 

 currents into the surrounding 

 water. One would naturally 

 expect that such apparently 

 helpless atoms would fall at 

 once to the bottom ; but in 

 such a case how could the 

 species be dispersed ? Here 

 we behold with wonder a beau- 

 tiful instance of providential 

 care. A power of locomotion 

 is conferred upon the offspring, 

 which is not possessed by the 

 parent sponge ; for whereas 

 the latter is firmly rooted to 

 the bottom, incapable of 

 changing its place, the little 

 germ is able to swim rapidly through the sea. This is effected 



FIG. ii. HALICHONDRIA OCULATA.* 



hals, the sea ; x 



chondros, cartilage. 



