ZOOLOGICAL AND BOTANICAL ASSOCIATION. 129 



Fig. 2. A single detached joint of the same, ^ of an inch in length, 

 magnified 330 diameters, showing the narrow or side view of 

 the compressed endochrome, and terminal granules as well as 

 one or two wandering motile granules remote from the end. 



Fig. 3. A portion of a filament of the same, the joints in this case t£?j of 

 an inch in length, magnified 200 diameters, showing at its 

 upper portion the lateral view, at its middle the oblique or 

 intermediate view, and at the lower end the front view of the 

 endochrome. The green contents of the continuous joints are, 

 however, in the same filament, usually disposed in the same 

 plane. The second and third joints from the top (shorter than 

 the others) illustrate the fact of recent self-division after the 

 manner prevalent in the Desmidiacese, as indicated by the 

 (as yet) not fully grown new portions of endochrome and 

 nascent halves, and the consequent still eccentric position of 

 the pale interruption, which in both joints is as yet consi- 

 derably nearer to the recently formed septum than when in its 

 ultimate regular central situation in the joint. [Of course, it 

 will not be assumed that the joints are always absolutely ma- 

 thematically straight. Although usually straight, some are 

 occasionally more or less curved, or even bent (the sides being, 

 however, always parallel), and this, no doubt, owing to ex- 

 ternal circumstances. I have drawn them not more curved 

 than they not unfrequently have presented themselves. Doci- 

 dium Ehrenbergii, for instance, is described as straight ; this 

 is its usual state ; but specimens sometimes occur bent almost 

 at right angles, and others sometimes with one segment, in 

 place of being of the usual narrow and elongate form, conside- 

 rably inflated, or almost globose.] 



Fig. 4. Exhibits the pressed-out cell-contents of Leptocystinema Kina- 

 hani, magnified 330 diameters, showing the gradually broken- 

 up central corpuscles, not "vesicles" — bodies similar, in fact, 



to those in Spirogyra, &c some entirely shattered, when they 



lose their light-coloured appearance ; also representing the 

 granules of the extruded cell-contents, as breaking off and set- 

 ting up their molecular motion in the surrounding water. 



Fig. 5. Three joints of a filament of Leptocystinema asperum ■ Docidium 

 asperum (Brib.), magnified 330 diameters, showing the con- 



ZOOL. * BOT. SOC. PBOC. VOL. I. 8 



