2i8 Hardy, A Red Euglena-. [^'Mardf** 



noticed that when exposed to direct sunshine gas-bubbles were 

 given off plentifully by the green form, but slightly by the red ; 

 and this and other circumstances suggest a character for E. 

 rubra more holozoic than holophytic. When red and green 

 organisms were mixed in approximately equal quantities, and 

 kept alive in water from a garden liquid-manure tank, the pro- 

 portion remained the same. Nor did the experiments with 

 the medium have any visible effect on the respective colours. 

 Proceeding on the theory of ingestion that led to Saville Kent's 

 rejection of E. sanguinea, I placed red Euglense in water from 

 the green Euglena pools, and vice versa, but found no result ; 

 and, having finely powdered the ferruginously-stained rock from 

 the red Euglena pool, could find no trace of an ingested particle 

 in any green or red organism. That any " mature phase " 

 should be absent from Euglense of all the waters of this 

 locality but this pool seemed unreasonable ; yet the possibility 

 of the deeper, colder, and comparatively dark pool producing 

 a phase that was not within the influence of the more open, 

 shallower, and consequently better lighted and warmer water 

 of the adjacent dams, still exists. 



When sunlight was withheld for a time, or the water tempera- 

 ture reduced, or the surface agitated, the green organisms were 

 the first to encyst. In experiments with cocaine, &c., it was 

 found that E. viridis was sooner narcotized than E. rubra. 



Although having the characteristic Euglenoid movement 

 and rotation on longitudinal axis which makes the progression 

 of the cell a boring one, these movements were all slower 

 than those of E. viridis under similar conditions of light, 

 medium, temperature, &c. The action of the flagellum also 

 was slower, the media used being dilute glycerine and water, 

 gum water (prepared from gum of Acacia pycnantha), &c. 



The surface striations or corrugations make, with the longi- 

 tudinal median line, an angle of about 30° or less, completing 

 not more than one spiral turn around the body, and are about 

 I ij. apart. If it be supposed that E. rubra is a large, lazy, 

 heterochromatic E. viridis, then the spiral markings might be 

 expected to be further apart on a distended cuticle. I have 

 not measured the striations on E. viridis. This spiral grooving 

 has, I think, some use in the boring progression of the Euglena, 

 much as a bullet is rotated by the rifling of the gun-barrel. Is 

 it not a fact that other flagellates lacking this spiral grooving 

 do not turn on the longitudinal axis as the Euglena does ? 

 The cuticle is faintly corrugated by this marking, each line 

 having a broken appearance. The effect is not given only by 

 markings or fibres seen through a smooth cuticular layer. 



Though published in 1900, Wagers' informative article on 

 the eye-spot and flagellum did not come under my notice until 



