q NATURAL HISTORY. 



to flow around its food, and that is all. By carefully watching we can 

 see the digestion taking place. The green of the plants is changed to a 

 yellowish brown, the protoplasm is extracted, and finally the indigestible 

 portions are cast out, or, rather, the Amoeba leaves them behind as it 

 moves along. 



Continued feeding makes an Amoeba fat, and its body soon oecomes 

 unwieldy. Corpulence is as great an inconvenience to it as to human 

 beings, but it has a remedy which they have not. It proceeds to divide 

 itself into two Amoebse, each like the other ; and, as one watches, he 

 cannot say which of the two was the parent and which the child. This 

 capacity for reproduction by division, taken together with some other 

 facts, led, a few years ago, to the idea that death, except as a result of 

 accident, was an unknown thing among the Protozoa ; but it would seem 

 that an error may exist here, and that among the Protozoa, as among all 

 living bodies, death is the regular sequence of life. The details of these 

 facts are too abstruse for repetition here, and, besides, to settle the ques- 

 tion, long and delicate experiments must be carried out. 



The Amoeba, like others of the Protozoa, has another mode of repro- 

 duction. At certain times it draws itself together, while the external 

 portion secretes a protective envelope. The internal protoplasm now 

 divides into a number of minute portions, which finally rupture the 

 enclosing wall, and escape as young Amoebae. 



There are many other Protozoa which, like the Amoeba, have the 



power of sending out large or small jDrotoplasmic 

 lobes or filaments. These are the group known as 

 Jk. ^ Rhizopods (root-footed). Some can secrete a pro- 



tective envelope, often of the most delicate texture 

 and beautiful pattern ; others cement together the 

 grains of sand in which they dwell, and form a case 

 ^ ^&&^ <tSs *^ to live in. Of the former group the Radiolaria and 



the Foraminifera deserve mention. The Radiolaria 



! are without doubt among the most beautiful products 



Fro.3.-Aradioiarian. in life f nature. A red or yellow protoplasm, enveloped 



the silicious skeleton is trans- , J J- r ? r 



parent and crystalline, the i n the most exquisite tracery of silicious spicules, 



granular contents orange. i ■> i- ' 



sometimes simple like the form figured, sometimes 

 of the greatest intricacy, is a poor description of the general beauty of a 

 Radiolarian. One needs to see them to appreciate them, or, in default 

 of opportunity, to turn over the plates of Haeckel's splendid mono- 

 graphs. 



The Foraminifera would take a high place were there no Radiolaria ; 

 but their shells, though beautiful, are heavy in comparison with those of 



