MONERA. 19 



whole, being surrounded and engulfed by the body, and the 

 protoplasmic matter is then absorbed, serving for the nour- 

 ishment and growth of the Moner. 



The simplest form known, and supposed to be really a living 

 being, is Haeckel's ProtanuBba. It may best be described 

 by stating that it is like an Ammia, but without a nucleus 

 and vacuoles (or little cavities). It reproduces by simple 

 self-division, much as in Amoeba (Fig. 11). 



In Protomonas the body is very changeable in form, the 

 pseudopods often being very slender, thread-like. Fig. 8, 

 A represents this Moner during the formation of the young 

 (zoospores) in the cyst-like body, or resting-stage of the 

 creature ; B, one of these germs freed from the cyst and 

 capable of moving about by the two thread-like pseudopo- 

 dia ; C D, the Amoeba-like form which the young after- 

 ward assumes, and which at maturity passes into the en- 

 cysted or resting-stage E. 



A still better idea of what a Moner is may be seen by 

 studying the Protomyxa aurantiaca Haeckel. 



This Moner was discovered at the Canary Islands. It is 

 from half to one millimetre in diameter, and is a perfectly 

 simple mass of orange-red jelly. When liungry numerous 

 root-shaped threads (pseudopodia) radiate from the central 

 mass. Fig. 9, E represents the Protomyxa after having 

 absorbed into its body-mass a number of shelled Infusoria. 

 When about to become encysted [A B) it rejects the shell 

 of its victims, retracts its false feet, and soon becomes fast- 

 ened as minute red balls to the surface of some dead shell. 



The ball becomes enclosed by a thick covering {A), and 

 then the contents become divided into several hundred small, 

 round, thoroughly structureless spheres, which become germs 

 {B). The germs finally burst through the cyst-wall, as in 

 G, a, c, d, and assume various monad-like and amoeboid 

 shapes, and finally attain, by simple additions of the proto- 

 plasm of its food (diatoms and infusoria), the adult form 

 yD E). Other Moners exist in fresh water. 



We have been dealing with the simplest living forms, be- 

 ings showing no trace of organization, much lower and 

 simpler than the Amoeba, with its nucleus. The individual 



