PROTOZOA 



B. Osculosa. 



Central capsule egg-shaped, with a principal aperture at the basal pole of the 

 chief axis. Skeleton siliceous, always extra- t 



capsular. Nucleus dividing late. 



III. Nassellaria. Capsular membrane simple, 

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

 Nassella, Cortina (Fig. 7), Cornutdla. 



IV. Phaeodaria. 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 (phseodium) in the 

 calymna. Aulospli<x,ra, Aulactinium (Fig. 8), 

 Cannopilus, Challengeria. 



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 ring 



^1^ 



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



part of life with one or more vibratile flagella, cleus ; dt, oil-drops ; pc, podoconus. 



FIG. 8. Aulactinium actinastrum, after Haeckel. n, Nucleus ; c, calymna 

 km, capsular membrane ; op, operculum ; ph, pliaeodium. 



