i6o 



THE MAST1GOPHORA 



ft. 



in the genera Mastigamoeba and Mastigina, recalling the relation of 

 the axial filament to the nucleus in certain Heliozoa (p. 23). 



At the base of the axial filament there is sometimes found a 

 minute granule, with peculiar staining properties, known as the 

 blepharoblast (Fig. 2, b), and closely associated with this there is 

 in the Trypanosomata l a small detached 

 portion of the nucleus known as the "kineto- 

 nucleus." 



At the base of the flagellum there is often 

 found a special vacuole into which the con- 

 tractile vacuoles may or may not open (Figs. 

 1 and 2). This is the flagellar reservoir. 

 In some forms (Trichomonas and Trypanoso- 

 mata) a delicate undulating membrane is 

 found at one side of the flagellum (Fig. 2, 

 p. 195). 



Besides the flagellate movements there are 

 two other important ways by which locomotion 

 can be effected by certain species, namely, by 

 amoeboid and by so-called metabolic or euglenoid 

 changes of shape, the former resulting in the 

 protrusion of pseudopodia, and the latter 

 involving alternate protraction and contraction 

 of the body, as may be observed in many 

 worms (Fig. 5 (28)), 



The possibility of executing amoeboid and 

 metabolic movements depends largely upon 

 pharynx ; c.st', cytostome ; the nature of the integument or pellicle which 



cst. ~. 



F10 . 2 . 

 Diagram of the struc- 



c.v, contractile vacuole > . . ,. 



fl, flagellum ; /., food- protects the protoplast from the surrounding 



vacuoles; N, nucleus; R, fl,,;^ rnprliiim 

 flagellar reservoir. (After nuia mea Um - 



Dobeii.) There are three principal kinds of integu- 



ment, with many degrees of differentiation : 



1. Periplast. This is an integral portion of the protoplast, from 

 which it is never separated and with which it divides. In naked 

 cells, such as Mastigamoeba, it appears as a simple ectoplasm covered 

 by a very thin pellicle (Fig. l,pel\ or as an alveolar layer of proto- 

 plasm (Multicilia). In most cases there is a more or less well- 

 defined pellicle or plasmatic membrane, which may be distinguished 

 under the name of proteid- membrane. This achieves its highest 

 development in the Euglenoidea, where it often presents a spirally 

 striated structure and resists decomposition (Fig. 5 (16, 17)). 



2. Perisarc. The perisarc does not, as a rule, form an integral 

 part of the protoplast, and does not usually divide with it, so that 

 after the division of the protoplast one of the fission-products issues 



1 For a discussion of the relations of these structures compare Dobell (3), 

 Minchin (13), Moore (14V T \*rtman and von Prowazek (5). 



