70 BEIT1SH FRESHWATER RHIZOPODA. 



narrowed anteriorly, and forming a conical lobe or 

 prominence from which emanates a long and active 

 flagellum. Psendopodia short, radiating outwards 

 from the cortical ectoplasm, simple or ramulose. The 

 body-surface, in at least one species, is habitually 

 covered with minute bacilliform spiculse. 



1. Mastigamoeba aspera F. E. Schulze. 

 (Plate VI, figs. 1-5.) 



Mastigamccba aspera F. E. SCHULZE in Arcliiv. f. mikr. Anat. 

 XI (1875), p. 583, t. xxxv ; ALLMAN in Journ. Linn. Soc., 

 Zool. XIII (1877), p. 268, f. 3; ARCHER in Q. J. Micr. 

 Sci. XVII, n.s. (1877), p. 350, t. xxi, f. 24; KENT Man. 

 Infus. I, pt. 2 (1880), p. 221, t. i, f. 21 ; LANESSAN Traite 

 Zool., Prot. (1882), p. 50, f. 38; BUTSCHLI in Bronn's 

 Thier-Reichs, I, 2 (1883), t. xxxix, f. 9; GRIFFITHS & 

 HENFKEY Micr. Diet, ed. 4 (1883), p. 492, t. liii, f. 22 ; 

 HERTWIG Lehrb. Zool. I (1891), p. 147, f. 43; ed. 2 

 (1900), p. 159, f. 113; and (Engl. transl.) Man. Zool. 

 (1903), p. 188, f. 118; CALKINS Prot. (1901), p. 103, 

 f . 57A. 



Animal, in the resting phase, sub-spherical or oval, 

 ultimately, when in active movement, becoming elon- 

 gated and narrowed anteriorly, whilst the posterior ex- 

 tremity remains rounded, or, in what may be younger 

 individuals, is produced into a rounded lobe. The body 

 is susceptible of considerable modifications, changing 

 from globular to oval, or becoming bluntly angular, 

 whilst throwing out numerous amoeboid pseudopodia, 

 in which condition the organism is hardly distinguish- 

 able from some forms of Amoeba, except by its highly- 

 refringent and denser protoplasm. In the mobile 

 state (PI. -VI, fig. 1) the pseudopodia are numerous, 

 variable in length, usually simple and straight, rarely 

 bigemiiiate or forked, mostly attenuated but blunt at 



e/ 



the apex, and never becoming filamentous or acicular. 

 The posterior ones are short; those immediately in 

 front, on either side of the frontal lobe, longer and 



