PROTOZOANS. 



FIG. 2. a, Amoeba throwing out 

 pseudopodia ; b, encysted. 



and contractile vesicles. They are either naked or 

 shelled. 



Order I. Foraminifera (Hole- Bearers). In the sim- 

 plest form, the Amoeba (Fig. 2), the body is divided into a 



transparent outer covering, and 

 an interior portion containing 

 thenuclei,and circulating gran- 

 ules that appear to be kept in 

 motion by the pulsation of the 

 contracting vesicle. It moves 

 along by throwing out pseudo- 

 podia, or false feet, and ingulfs 

 its food desmids, diatoms, and 



other minute forms as does the moner. The Amoeba 

 reproduces by simple division. 



Shelled Amoebae. These forms (Fig. 3) secrete rich 

 calcareous or horny chambered shells, from which are 

 thrown out the false feet, 

 extending in every direc- 

 tion in search of prey, and 

 fusing about it without the 

 shell. They are generally 

 minute, but one found off 

 Borneo measures two inch- 

 es across. They reproduce 

 in different ways ; in one, 

 the young resemble monads 

 (Fig. 6), finally assuming 

 the parent form. 



Order II. Radiolaria 

 (Rayed Animals]. In these 



animals (Fig. 4) the false feet are generally pointed, and 

 the shells, which are formed of silica, not lime, are richly 

 ornamented with spicules, or rays, and perforated with 

 openings for the pseudopodia, that secure their food, as we 

 have seen in the Foraminifera. They reproduce by di- 



FIG. 3. Rotalia, with extended pseu- 

 dopodia. 



