108 AUSTRALIAN FRESHWATER FLAGELLATES, 



Genus M A L L M N A s Perty. 

 Mallomoxas acaroides Perty. (PI. ii., tigs. 1, 2). 



Cell. long-. 21—42, lat. 12—23 ; setae long. 12—30^1. 



Auburn; Guildford (84); Pairamatta (13G); Clyde; Wviallali; Lismore 

 (2G1, 287). 



Syn. Mallomonas Plosslei Perty, see Kent. PI. .xsiv.. f. 72, 73; Lepidoton 

 dubium Seligo. Many forms of this species may be found, as it is very variable 

 in its growth. I have noted subglobose, oval, ovate pointed in front, ovate 

 pointed behind, eUiptic; but probably they are all growth forms of one and the 

 same organism. There is evidence to show that MaIlom<itias develops from a 

 small globose cell, and according to its rate of growth, and the line of develop- 

 ment that it takes, so is the resulting form. In every si>ecies the fully-de- 

 veloped form is lintiar-elliptie or oljlong-elliptic. In M. acaniideii also the cell 

 may be furnished all over with setae, or some ]iart of the surface may be de\'oid 

 of them, or again they may be entirely wanting, and occasionally they are so 

 delicate as almost to escape observation. Cells as low down as 14 x lo^ have 

 been noted. Perty's type is really an immature form of the species, and these 

 may generally be recognised by having tlie c.v. at the hinder end; in the mature 

 form they are set in a circle at the posterior third of the cell. Compare here 

 M. elegans Lemm., Schwed. Gewasser, f. 14, and M. tiDisurata Telling, Schwed. 

 Plankt., i., flg. 3. 



Mallomoxas splendens (6. S. West) Playf. (Pi. ii.. fig. 3). 



Cell. long. 30—56, lat. 9—13; setae long. 10—36^. 



Auburn; Sydney Water ((i4. 80. 81); Botany (142); Botanic Gardens (3); 

 Wyrallah; Lismore (241. 260. 261. 316). 



Syn. Lagerlieimia sjjletidens G. S. West, Algae Yan Yean Reservoir, p. 

 74, Ph 6, f. 4 — 8. .Judging by my records this species is even more common in 

 our waters than M. acaroides, and it is generally found in the; mature shape. 

 if not always the full size. Indeed, I know of only one young form {infra). 

 There may be any number of setae from 2 to 4 before and behind. They differ- 

 from the setae of M. a<;ar(iides, which are like very fine bristles, in being stouter, 

 of a spinous nature and inflated strongly at the base. Those in front are gener- 

 ally carried at right angles to the body, the hinder group project right back , 

 they are capable of a slight amount of lateral nio\-ement. 



Var. I'UsiLLA, u.var. (PI. ii.. fig. 4). 



Forma nuilto-brevior, oblongo-ovalis. setis nullis observatis. membrana 

 glabra, striis obliquis 3 — 4 decussatim dispositis ornata. 



Cell. long. 10—17, lat. 8— 12J^. 



Sydney Water (80. 81); Centennial Park. Sydney; Byron I'.ay. 



Probably a young form either in process of growth or fi.xed by incrassa- 

 tion of the cell wall before reaching maturity. It is much shorter than the 

 type though almost as broad as a full-growTi specimen. Oblong-oval in shape, 

 membrane smooth, crossed by 3 or 4, very fine, obliquely disposed, criss-cross 

 grooves having the appearance of striae. No .setae in the specimens noted. 



