PHYLUM PROTOZOA 



4' 



transverse groove which completely encircles the body ; the 

 former alone acts as an organ of locomotion, the latter lies 

 habitually in the groove and performs undulating move- 

 ments. Noctiluca (Cystoflagellata) (Fig. 16), which is the 

 largest member of the class, being about half a millimetre 

 in diameter, has two flagella, one of which is modified in 

 a remarkable manner. The body of Noctiluca is globular, 

 with a cleft along one side so that it resembles a miniature 

 peach. From this springs a very large and stout flagellum 



f 



'■■lq 



Fig. 16. — Noctiluca miliaris. a, the adult animal; b, c, flagellulse; l>g, tentacle; 

 f t flagellum; tu, mouth; h, nucleus. (From Lang, after Eiitschli.) 



or tentick, which is marked with a number of transverse 

 lines or striations ; and a second flagellum, of comparatively 

 small size, lies in the gullet. 



Though all the Mastigophora are characterised by the 

 possession of flagella, there are a few, such as Mastigamxba 

 (Fig. 13, 4), which also possess pseudopodia, and may be 

 capable of amoeboid movements. 



. Nutrition is effected in a variety of different ways. Some 

 .forms live in decaying organic infusions, not taking in solid 

 food-particles, but absorbing nourishing matter in a dis- 



