BTE-SPOT AND FLAGELLTJM IN EUGLENA VIUIDIS. 471 



investigated, but the few observations which have been made 

 seem to show that it is a chlorophyll derivative. According to 

 Cohn, with whom Klebs agrees, the red pigment is hsemato- 

 ehrorae, and stands in genetic relationship to chlorophyll; 

 whilst Rostafinski * regards it as reduced chlorophyll. The 

 rusty-red granules and the pigment of the eye-spot are similar 

 in their behaviour towards alcohol, which in both cases, imme- 

 diately it comes into contact with them, causes the granules 

 to run together to form a homogeneous red mass or drop of oily 

 substance, from which two colouring-matters at once become 

 separated out — an orange-coloured substance which forms the 

 main mass of the drop, and one or two small bright red droplets in 

 the centre of it. The red colour soon disappears entirely, and the 

 orange colour changes to yellowish green, then to green, and at 

 the same time becomes smaller and smaller until it suddenly 

 disappears , and in its place a small vacuolar-like body is left, 

 surrounded by an irregular ring of some refractive substance. 



This reaction, although not conclusive by any means, indicates 

 that the rusty-red granules which are derived from the chloro- 

 phyll and the red pigment of the eye-spot have something in 

 common, and supports Cohn's statement that the latter is 

 genetically connected with chlorophyll. It has been suggested 

 that the pigment of the eye-spot is identical with the red 

 colouring-matter, carotin, which occurs in the roots of Daucus 

 Garota and in the orange or red chromatophores of many fruits 

 and flowers, from the fact that it shows the characteristic blue 

 colour with sulphuric acid t. 



Gruignard J has shown that in the Fucaceae the orange- 

 coloured chromatophores possess the same chemical reactions as 

 the orange-coloured eye-spot ; and he further shows that the 

 €ye-spot is formed from a colourless chromatophore found on one 

 side of the nucleus, which at first becomes rapidly coloured yellow, 

 then orange. 



In Euglena the eye-spot is found both in the motile and in the 

 resting cells, and new eye-spots arise by division, as Klebs has 

 also shown. Whether there is any formation of eye-'spots de 

 novo at any stage in the life-history of Muglena, such as occurs in 



* Klebs, I. c. 



t See Zimmermann, Botanical Micro-technique. 



+ Revue Gea. de Bot. i. 1889. 



36* 



