404 ON THE STRUCTURE AND HABITS 



nutritious particles, is driven out by the larger orifices. The large and small 

 orifices, with the tubular passage intervening, are represented at Fig. 3. — The 

 discovery of this singular fact — which entitles these objects to be considered 

 as animals — is due to Dr. Grant, in whose beautiful language I cannot do better 

 than give you an account of the discovery : — " I put," says he, " a small branch 

 of the Spongia coalita with some sea- water into a watch-glass, under the micro- 

 scope, and on reflecting the light of a candle through the fluid, I soon perceived 

 that there was some intestine motion in the opaque particles floating through the 

 water. On moving the watch-glass, so as to bring one of the apertures on the 

 side of the Sponge fully into view, I beheld, for the first time, the splendid 

 spectacle of this living fountain, vomiting forth, from a circular cavity, an im- 

 petuous torrent of liquid matter, and hurling along in rapid succession opaque 

 masses, which it strewed every where around. The beauty and novelty of such 

 a scene in the animal kingdom, long arrested my attention, 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 assume a variety of forms and shapes, some of them very singular 

 and beautiful. They are, however, best known to us in the form of Common 

 Sponge. 



The next group of animals on which I shall remark are called Radiata, on 

 account of the manner in which their parts are arranged. This section of the 

 Animal Kingdom is divided into two parts, the Gelatinous Radiaries and the 

 Spiny-skinned Radiaries. Of the former the Jelly-fish is an instance, of the 

 latter the Star-fish. Amongst the Jelly-fish we find a little lucid creature. 

 This animal is very abundant in the ocean, and literally crowds it in some places ; 

 they are, however, so lucid as to be seen during the day ; but in tropical climates 

 they are phosphorescent, and it is when the light of the day is retiring that these 

 creatures frequently present a brilliant spectacle to the delighted eye of the 

 traveller of the ocean. First one is seen and then another, then hundreds, and 

 thousands and tens of thousands, till the whole ocean is covered with an unin- 

 terrupted blaze of phosphorescent light. 



The Common Jelly-fish or Sea-nettle (Medusa) is another form of this class of 

 animals, and must be well known to those who have been in the habit of sailing 

 or rowing on our seas and estuaries. The elegant contractions and expansions of 

 its lucid body, as it gracefully moves along the waters, excite alike our curiosity 

 and admiration. 



