Vorticellina.'] THE INFUSORIA. 255 



like, as seen in the engraving, fig. 235 and 236 (plate v.) ; the 

 lateral crest and frontal wreath, or crown of cilii, are con- 

 tinuous. When kept in glass vessels they often fix them- 

 selves to the sides in clusters. Self-division has not yet 

 been observed. They are best examined under a micro- 

 scope, when placed in a large live-box. A magnifying 

 power of 100 diameters is sufficient. Found amongst 

 vaucheria. Length 1 -480th. 



387. STENTOR polymorphus. The green Stentor resem- 

 bles the preceding in form. The ova are of a beautiful 

 green-colour, the gland articulated and chain-like, the 

 lateral crest indistinct, and the frontal wreath of cilii 

 interrupted. This species will not receive indigo readily. 

 Transverse self-divison has been observed. Found upon 

 stones, decayed sticks, and leaves, in standing water. 

 Length 1-1 20th to l-24th. 



388. STENTOR igneus. The fire-coloured Stentor is less 

 than the preceding, the ova is of a yellowish-green colour, 

 the skin bright yellow or vermillion, the gland is spherical, 

 lateral plume or crest absent, and the frontal wreath of cilii 

 interrupted. Found by Ehrenberg upon the water violet 

 (Hottonia palustris). Length l-72nd. 



389. STENTOR niger (Vorticella nlgra y M.) The 

 brownish- black Stentor is small, of a dark brownish- 

 yellow or blackish colour, the ova olive coloured, the 

 gland is spherical, the lateral crest absent, and the frontal 

 wreath of cilii continuous. This species is often so abun- 

 dant that it colours large pools, in turfy hollows, of a dark 

 black, resembling an infusion of coffee. The swimming 

 movement of this species is readily seen (as in the others) 

 with the naked eye. Size l-96th. 



