6 PROTOZOANS. 
and contractile vesicles. They are either naked or 
shelled. 
Order I. Foraminifera (Hole-Bearers).—In the sim- 
plest form, the Ameba (Fig. 2), the body is divided into a 
transparent outer covering, and 
an interior portion containing 
the nuclei,and circulating gran- 
ules that appear to be kept in 
motion by the pulsation of the 
contracting vesicle. It moves 
Fic. z.—a, Amoeba throwing out along by throwing out pseudo- 
pseudopodia ; 4, encysted. podia, or false feet, and ingulfs 
its food—desmids, diatoms, and 
other minute forms—as does the moner. The Ameba 
reproduces by simple division. 
Shelled Amcebzx.—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. Fic. 3.—Rotalia, with extended pseu- 
Order II. Radiolaria anpedia. 
(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- 
