46 EUGLENA 



chlorophyll which tinges all the central part of the body, 

 the two ends being colourless. It is difficult to make out 

 whether the chlorophyll is lodged in one chromatophore or 

 in several. 



In Haematococcus we saw that chlorophyll was asso- 

 ciated with starch (p. 27). In Euglena there are, near the 

 middle of the body, a number of grains of paramylum 

 (H, p) a carbohydrate of the same composition as starch 

 (C fi H 10 O 5 ), but differing from it in remaining uncoloured 

 by iodine. 



Water containing Euglena gives off bubbles of oxygen in 

 sunlight : as in Hsematococcus the carbon dioxide in solution 

 in the water is decomposed in the presence of chlorophyll, 

 its oxygen evolved, and its carbon combined with the 

 elements of water and used in nutrition. For a long time 

 Euglena was thought to be nourished entirely in this way, 

 but there is a good deal of reason for thinking that this is 

 not the case. 



When the anterior end of a Euglena is very highly 

 magnified it is found to have the form shown in Fig. 5, F. 

 It is produced into a blunt snout-like extremity at the base 

 of which is a conical depression (ees) leading into the soft 

 internal protoplasm : just the sort of depression one could 

 make in a clay model of Euglena by thrusting one's finger or 

 the end of a pencil into the clay. From the bottom of this 

 tube the flagellum arises, and by its continual movement 

 gives rise to a sort of whirlpool in the neighbourhood. By 

 the current thus produced minute, solid food-particles are 

 swept down the tube and forced into the soft interna 

 protoplasm, where they doubtless become digested in the 

 same way as the substances ingested by an Amoeba. That 

 solid particles are so ingested by Euglena has been proved 

 by diffusing finely produced carmine in the water, when the 



