468 MK. HAROLD WAC4EB ON THE 



absorbed tlirougli the gullet, and he brings forward the following 

 observation in support of this view. When Euglence are kept 

 in dilute potato-starch solution in the dark, paramylum grains 

 are produced in great abundance, gradually filling up the whole 

 cell, and pushing the chlorophyll granules to the posterior end 

 of the cell. The smallest paramylum grains are found at the 

 anterior end of the cell in the neighbourhood of the gullet; and 

 they gradually increase in size towards the middle of the cell, 

 where they are much crowded together and nearly all of the 

 same size. KhawMue's explanation of this is that the small size 

 of the grains near the gullet indicates that they begin to form 

 in this region, and that it is probably through the gullet that 

 the substances are absorbed which are necessary for their 

 production. 



This is a very interesting observation ; but it is obvious that 

 we require further evidence before we can say definitely that 

 liquid nutriment is absorbed wholly, or even partly, through the 

 gullet. 



So far, then, all we can say concerning the function of this 

 anterior cavity in the cell of Euglena is that it serves for the 

 excretion of liquid from the pulsating vacuole ; but that it serves 

 for the ingestion of either solid or liquid food has not been proved. 

 In a later part of this paper I shall refer to its connection with 

 the flagellum. 



Structure of the Eye-spot. 



It is well known that many motile cells of both animals and 

 plants possess a red pigmeut-spot which is sharply defined 

 from the protoplasm ; and, from its apparent resetublance to 

 the eye of Cyclops and Eotifers, was called by Ehrenberg an 

 eye-spot. 



Our knowledge of its structure depends upon the researches 

 of Leydig, Kunstler, Klebs (I. c), Schilling, Franze *, Overton t, 

 Pouchet, Johnson +, and others, for an account of which reference 



* Frauze, " Zur Morphologie und Physiologic der Stigmata der Mastigo- 

 phoren." Zeit. f. Wiss. Zool. 1893, vol. Ivi. p. 138. 



t Overton, " Beitrag zur Kentniss der Gattung Volvox." Bot. Centralbl. 

 Tol. xxxix. p. 65, 1889. 



I Johnson, " Observations on the Zoospores of Draparnaldia." Bot. Gae. 

 Tol. xviii. p. 294, 1893. 



