222 



THE ANIMAL KINGDOM. 



The Zoophyte which dwells in these tubes is furnished with a 

 set of cilia forming a sort of plume. Most of these Hydroida 





TIG. 5. FKAGMENT OF SPONGE, MAGNIFIED. 



are phosphorescent, such are those which, scattered about 

 on the surface of the sea, contribute to that luminosity so 

 frequently seen. 



The second order of the Zoophyta, Asteroida, are those 

 which have a star-like shape ; they are 

 congregated into compound structures, 

 forming what are called sea-fans (Gor- 

 gonia, fig. 6) . These Gorgonia are of all 

 colours, and very beautiful ; the animals 

 or " polypes " are gelatinous, and have a 

 gelatinous mass or stalk with branches, 

 strengthened and supported by a horny 

 centre. This gelatinous mass forms the 

 animal itself, as well as a sort of common 

 integument connecting the whole family 

 of many thousands. The Gorgonia or sea- 

 fans usually preserved, are dry and hard, 

 as the gelatinous covering has so little 

 substance that, when dried, it forms a 

 rough powdery covering only to the 

 horny support. This powdery surface, 

 if washed off with a little water and 

 placed under the microscope, is found 

 to contain and be made up of spicula? 

 or crystals of carbonate of lime, of 



Tr. P>. GORGONIA GUT- ^ -t -, -i , n i c* 



TATA (Natural size), various colours and beautiful forms 



