288 FAMILY: MONADID^ 



10. Family: DINENYMPHID.E Grassi, 1911. — Flagellates which have 

 several flagella, the axonemes of which are directed backwards and 

 attached to the borders of a series of undulating membranes. There is an 

 axostyle, as in the Trichomonadidae. 



(2). Suh-Order : Craspedomonadea, 

 The sub-order Craspedomonadea includes flagellates which are more 

 or less permanently attached to objects (Figs. 16, 17, 18). The point of 

 attachment is the posterior end of the body, and from this a filament may 

 be secreted, at the end of which the flagellates wave about. In some cases 

 the filament becomes a complex, tree-like system with a flagellate at the 

 extremity of each branch. Each attached flagellate may develop around 

 itself a gelatinous or chitinous cup-like sheath or lorica. The latter is 

 formed both by attached flagellates, which have no filaments, as well as by 

 those which possess them. Another modification undergone by some of 

 these attached flagellates is the development of a cytoplasmic cylindrical 

 collar or cuff with overlapping margins round the base of the flagellum 

 at the anterior end of the body. The collared forms may or may not have 

 loricae as well. The Craspedomonadea are not parasitic forms, and they 

 often appear in fluids containing decomposing vegetable matter such as 

 hay infusion. They need not be considered any further here. 



SYSTEMATIC DESCRIPTION OF THE GENERA AND SPECIES IN 

 THE FAMILIES OF THE SUB-ORDER EUMONADEA. 



The flagellates in this sub-order are unattached, free-swimming forms, 

 some of which are parasitic, though the majority are not. They include 

 types with a single flagellum and very simple structure, and a series of 

 transition forms leading to more complicated flagellates with at least 

 six flagella. 



1. Family: MONADID^ Kent, 1880. 



The flagellates belonging to this family include the simplest of the 

 Mastigophora. They possess one or more flagella, the axonemes of 

 which take origin in blepharoplasts which are situated either upon 

 the nuclear membrane or separate from it. When there is more 

 than one flagellum all may be directed forwards, or one may be 

 differentiated as a trailing flagellum. A cytostome may or may not be 

 present, while the body is often liable to marked amoeboid changes of 

 form. Apart from the nucleus, blepharoplasts, and axonemes there are 

 no internal structures except the food vacuoles and the contractile 

 vacuoles in the non-parasitic forms. The Monadidse could be subdivided 



