150 DE9CBIPTI0N OF \Folygastrica. 



Dujardin's opinion, seeing that these beings are sensitive of light 

 and, like plants, fix themselves to the lightest part of the containing 

 vessel, and disengage gas (oxygen) when exposed to the sun's rays. 

 In the green substance are seen granular masses, a disc with en- 

 larged border and a red speck. The motor filaments proceed from the 

 same opening of the integument, and often form a diaphanous lobe 

 projecting from the opening. The red colour seen oftentimes in the 

 water of the Mediteranean appears due to Infusoria of this genus. 



DisELMis, vvridis = chlamidomonas puhisculus, (Ehr.) 



D. marina. — Body nearly globular, obtuse, and rounded in front, 

 granular within. Length l-1050th. 



This species is larger than D. viridis, more globular, and appa- 

 rently deficient of the red speck. Found in stagnant sea water of a 

 gi'een colour. 



D. Angusta. — Body pyriform, oblong, appearing to be plaited, and 

 tubercular inside, sometimes with an indistinct red speck. Length 

 1- 2600th to 1-1 850th. 



D. Dunalii. — Body oval or oblong, often constiicted about the 

 middle; colourless when very young, then green, afterwards red, 

 two flagelKform filaments longer than the body, seated on a pro- 

 jecting and retractile anterior lobe. Interior occupied by coloured 

 globules. Discovered by M. Joly, to be the chief cause of the red 

 colour of the water of the Mediterranean Sea. 



Genus Anisoi^ema. — Body colourless, oblong, more or less com- 

 pressed, having a resistant envelope, giving exit by an opening to 

 two filaments, one directed forwards flagelliform, the other trailing 

 backwai'ds and retractile ; movement slow. 



In other genera, as in Heteromita, two similarly characterized 

 filaments exist, but the present genus is known by its non- contractile 

 resistant integument, which is often met with empty and transparent. 

 It may be that the Bodo grandis (Ehr.) is allied to this genus as 

 well as to Heteromita. 



A. acinus. — Body oblong, depressed, rounded posteriorly narrower 

 in front, like the seed of an apple, with an opening close to the apex ; 

 movement in a straight line forwards. Length 1-1 300th to 1 -850th. 

 In pond water. 



A. sulcata. — Body oval, depressed, with 4-5 longitudinal fuiTOws, 



