PROTOZOA 



37 



CLASS III. MASTIGOPHORA 



The Mastigophora (Gr. fxaari^, a whip, and $epw, to bear) 

 are often known as the Flagellata (Lat. flagellum, a whip), but 

 at present the latter term is usually restricted to the first order 

 under this class. They are distinguished from the other Pro- 

 tozoa by the fact that each individual possesses one or more 

 delicate, elongated, protoplasmic processes, the flagella, which 

 function as the chief organs of locomotion. They are found in 

 fresh and in salt water, living singly and in colonies, and some 

 exhibit relationships either structural or functional with the 

 Rhizopoda and with plants. 



Order i. Flagellata 



The Flagellata exhibit great dive 

 distinguished from the rest of the 

 absence of those structures which 

 are characteristic of the other 

 orders. There is always a flagel- 

 lum at the anterior end of the 

 animal, and frequently two, and 

 others may be present on other 

 parts of the body. 



The shape of the body may be 

 more or less irregular (Fig. 17), 

 spherical, ellipsoid, ovoid, or elon- 

 gated (Fig. 18), or colonies may 

 be formed, spherical (Figs. 19, 20, 

 and 21), or branched in various 

 ways (Figs. 19 and 22), the latter 

 often remarkably beautiful. There 

 is generally a single nucleus, a con- 

 tractile vacuole, and often a bright 

 red pigment spot, which is sup- 

 posed to be sensitive to light. In 

 some, numerous colored granules 

 are present, either greenish, due 

 Many Flagellata are naked, i.e. the 

 definite membrane ; others have 



rsity of form and are to be 

 Mastigophora chiefly by the 



/; JfrX* •■;■/•■»,"•■':■«/ £X — 

 tvV.T.'; •--'-!« 



M 



FIG. 17. Mastigamoeba aspera. f, fla- 

 gellum ; p. pseudopodium. (After F. 

 E. Schultze, from Calkins' Protozoa.) 



to chlorophyll, or reddish, 

 body is not bounded by any 

 a thin cuticula, and some 



