! PROTOZOA 



B. Osculosa. 



Central capsule egg-shaped, with a principal 

 chief axis. Skeleton siliceous, always extra- 

 capsular. Nucleus dividing late. 



III. Nassellaria. Capsular membrane simple, 

 a porous area at the oral pole of the chief axis. 

 Nassclla, Cortina (Fig. 7), Gornutclla. 



IV. Phseodaria. Capsular membrane double ; 

 at the oral pole of the principal axis an osculum 

 closed by a radially striped lid, with a central 

 opening produced in the shape of a chimney. A 

 collection of pigment bodies (phaeodium) in the 

 calymna. Aulosplmra, Aulactinium (Fig. 8), 

 Cannopilus, Challcngeria. 



CLASS III. Flagellata (Mastigophora). 



Organisms which are unicellular or united into 

 simple cell colonies ; properly standing on the 

 boundary line between the animal and vegetable 

 kingdoms, since some groups are directly con- 

 nected morphologically and physiologically with 

 the lowest plants, others, chiefly by their manner 

 of taking nourishment (ingestion of solid food), 

 with animals. Furnished during the principal 

 part of life with one or more vibratile flagella, 



aperture at the basal pole of the 



FIG. 7. Cortina typus (after Haec- 

 kel) not quite fully drawn, s, Skeletal 

 ring; 1, 2, 3, 4, principal rays ; n, nu- 

 cleus ; ot, oil-drops ; pc, podoconus. 



Fio. 8. Aulactinium actinastrum, after Haeckel. , Nucleus ; c, calymna ; 

 /.m, capsular membrane ; op, operculum ; ph, plueodiuin. 



