248. LEISURE-TIME STUDIES. 



distinguishing between the most highly organised animals, 

 and plants of equal rank. Take, for example, the very 

 obvious characteristics which appear to be presented by the 

 form of animals and plants respectively, bearing in mind, 

 of course, that our object is that of constructing a definition 

 of an animal or plant which shall hold good alike of the 

 highest and lowest members of each series. If the out- 

 ward appearance of animals and plants, which forms so 

 satisfactory a guide to distinction in the case of the higher 

 forms of each group, be relief upon as a means of separation 

 in lower life, we speedily find ourselves involved in confusion 

 and perplexity. For very many true animals are found to 

 present the closest possible resemblance to plants, and 

 many undoubted plants of lower kind mimic in a marvellous 

 manner the likeness of their animal neighbours. The green 

 fresh-water sponge, common in our canals and rivers, closely 

 resembles a plant-organism in colour, appearance, and mode 

 of growth, although it is at the same time worthy of remark 

 that there are a few naturalists, who, in opposition to the 

 well-founded opinions of their brethren, still advocate the 

 ancient idea that sponges should be relegated to the care of 

 the botanist. 



More remarkable, however, in respect of their close re- 

 semblance to plants, are those curious colonies of undoubted 

 animals to which the names of zoophytes and polyzoa 

 have been given. The oyster-dredger is very familiar with 

 the zoophytes or "sea-flowers" (Fig. 36), as he terms them, 

 which grow in rich clusters attached to oyster-shells, to 

 stones, and to other objects obtained from the depths of the 

 sea. Each zoophyte grows rooted and fixed like a plant, 

 possesses usually a well-defined stem and branches, and 

 closely imitates in other respects the life and form of a 

 plant. The writer has before him at present a specimen of 

 a beautiful genus of zoophytes named Plumularia, which 

 raises its various stems in beautiful clusters from the shell 

 to which it is attached, and which, as preserved for the 

 museum, presents the most accurate reproduction of a plant 



