Zi ZOOLOGY. 



its body. The Amoeba reproduces its kind by simple di- 

 ■vision, as seen in Amceba spharococcus Haeckel (Fig. 11). 

 This species, unlike others, so far as known, becomes encysted 

 {B), then breaks the cell- wall and becomes free as at A. 

 Self-division then begins as at C, the nucleus doubling it- 

 self, until at D a and I) b we have as the result two individ- 

 uals. 



Order 1. Foraminifera. — Besides Amaba, sereral other 

 forms, either naked or shelled, produce, by division of an in- 

 ner portion of the body, numbers of ciliated young, as in 

 the naked Pelmiyxa, in certain many-chambered Fora- 

 minifera, and in CoUospha- 

 ra. An example may be 

 seen in the European Pelo- 

 ■myxa palustris Greef (Tig. 

 1"2\ This creature lives in 

 the mud at the bottom of 

 fresh- water pools, and when 

 first seen resembles little 

 dark balls of mud a milli- 

 metre in diameter. Instead 

 of one nucleus, there are 

 numbers of them, and nu- 

 „ , „ , , merous contractile vacuoles 



^- y^—Pdomyxa palmlns. 4. a, clear „,, , .., n -t , 



cortical pomon; 6, diatoma enclosed in the Illlea With a nUlQ, tosrether 

 body-mass. S, amoBba-liiebodieeoriginatiiiK •,, . , mr 



from the nuclei, which after leaTing the body With SpiCUleS. J he VOUUg 

 pass into monad-iike forms, O; n, nucleus : i. c l i. ti " . rt\ 



«, contractile Tesicle.— After Greef. ^ire at Iirst amoeba-llKe (ijj. 



originating as " shining 

 bodies," which have resulted from the self-division of the 

 •nuclei. These amoeba-like bodies finally assume an active, 

 monad-like stage C, and move about by means of a cilium 

 or lash. 



We now come to the shelled Amoeba?, or genuine Forami- 

 nifern. A common type is Arcella, which secretes a one- 

 chambered silicious shell, found in fresh water, and a 

 representative of the monothalamous, or one-chambered, 

 Foraminifera; while the many-chambered forms are 

 marine, of which Globigerina bulloides (Fig. 13), found 

 floating on the surface of the ocean, with its pseudopodia 



