250 Mr. H. J. Carter on Filigerous Green 



from the increasing red colour of the contents of the Euglenrc 

 generally (fig. 10). 



Obs. The peculiarity of this Euglena, as before stated, con- 

 sists entirely in the trumpet-shaped extension of the cyst (11a), 

 which, no doubt, allows the cilium to play freely in the water 

 beneath, probably for aeration and nutriment during the time 

 that the Euglena is multiplying itself in the way above men- 

 tioned. I observed this phenomenon for two successive years, 

 in the deep tank formed out of an old quarry in the trap-rock 

 of the garden of the Hope Hall hotel at Bombay, where the 

 brilliant red colour which it presented was most remarkable. 

 There did not appear to be any rule for the commencement or 

 extension of the process of reddening in the chlorophyll ; for 

 sometimes it began in the middle, sometimes at one end, and 

 sometimes at the other, of the Euglena. 



Euglena agilis, Cart. (Ann. ser. 2. vol. xviii. pi. 6. fig. 62, a-d). 



So named from its active movements. It is further charac- 

 terized by its flask-like form, the enlarged end being posterior; 

 by its double spherical nucleolar cell, and its short, blunt, 

 caudal prolongation when this is present, Avhich is not always ; 

 also by its remarkable tendency to multiply itself both in the 

 active and passive or encysted state — that is to say, dividing 

 longitudinally or transversely in the former, and crucially and 

 linearly in the latter, the linear division resulting in short 

 filament-like forms, in which each cell has an eye-spot. Add 

 to this its brackish-water habitat in the island of Bombay. 



I ought to have given this detail with my figure in the 

 1 Annals ' of 1856, vol. xviii., as the remark in the last edition 

 of Pritchard's ' Infusoria' (1861) justly indicates. Hence its 

 publication now. 



Uoella bodo, Ehr. 



Those who are acquainted with the great tribe of green 

 filigerous Infusoria, of which Euglena viridis is at once the 

 commonest and most beautiful type, are aware that the course 

 of individual increase, both with and without the true process 

 of generation, in this tribe is effected by division of the cell- 

 contents, within the cell, into a greater or less number of 

 parts. 



In the true process of generation, the division for the female 

 element ceases while the divided portions are yet large, but 

 goes on to a more or less minute degree for the spermatic ele- 

 ment, when the two, afterwards meeting under favourable 

 circumstances (that is, while both the elements are still plastic, 

 and neither surrounded by a closed cellulose wall), complete the 



