THE MASTIGOPHORA 



191 



Fio. 15. 



Nwtiluca miliaris, Suriray. 1, 2, two stages in the longitudinal lission ; n, nucleus ; N, 

 food - particles ; t, tentacle. 3, aboral view; a, entrance to the peristome ; c, the bacillary 

 organ ; d, the tentacle ; ft, the nucleus. 4, the animal acted upon by iodine solution, showing 

 the protoplasm like the "primordial utricle" of a vegetable cell shrunk away from the cuirass. 

 5, lateral view, showing (a) the entrance to the peristome in which 6 is placed ; <;, the bacillary 

 organ ; <?, the tentacle ; e, the mouth and pharynx, in which the flagellum is situated ; /, broad 

 plexus of tibrillae passing from the central protoplasm to the bacillary organs; h, nucleus. 

 After Lankester.) 



SUB-CLASS VI. SILICOFLAGELLATA. 



This division of the Mastigophora affords an apparent transition 

 from the Flagellata to the Radiolaria. It is monotypic, compris- 

 ing the single species Distephanus speculum, Stohr, which is para- 

 sitic upon or commensal with Radiolaria, and while possessing a 

 flagellum, has also a fenestrated siliceous skeleton. 



LITERATURE. 



Since the publication of Biitschli's treatise on the Mastigophora in Bronn's 

 Klassen und Ordnungen dcs Tfiicrreichs, Bd. i. Abth. 2, 1885, this class of 

 Protozoa has received the fullest general treatment in the pages of Engler and 



