254 DESCRIPTION OF [Polygastrica. 



white funnel-like polypi discovered by Trembly; it is 

 large, the crown or wreath of cilii is interrupted, and the 

 lateral crest of fringe is indistinct. When swimming, the 

 animalcule is usually contracted in the form of an egg, 

 but when attached, it stretches itself out, like a trumpet. 

 When several are swimming in a glass vessel, they will 

 gradually congregate, and select some particular spot, and 

 then attach themselves, evincing, as it were, not only a 

 degree of sociality, but, says Ehrenberg, a mental activity. 

 These animalcules feed upon coloured food very readily ; 

 the ova are white, the spermatic gland moniliform. When 

 kept a long time in cylindrical glass vessels they fasten 

 themselves to the sides, form a slimy covering around 

 them, and die. Found upon lemna and other water- 

 plants, even under ice. Size, stretched out, l-20th ; con- 

 tracted, 1-1 20th. 



385. STENTOR Roeselii. Roesel's Stentor. In form, size, 

 and crest, this resembles the preceding species, as shewn, 

 elongated, at fig. 233; and contracted, as it swims, at 

 fig. 234 ; the latter representation is rather more magnified. 

 The seminal gland is long, non-articulated, ribbon- 

 shaped, as seen in the engraving. Above the gland are 

 seen two of the stomach- cells, and the crest or fringe; 

 at (*) is the contractile vesicle. In colour this species is 

 more of a yellowish-white than the preceding. Found 

 upon flocky decaying reeds, leaves &c. Common, in 

 summer, in standing water on stones. Length 1-1 40th ; 

 extended, l-24th. 



386. STENTOR caeruleus. The blue Stentor, or funnel- 

 shaped Polypi, resembles, exteriorly, the two preceding spe- 

 cies, but the ova are blue ; the gland is articulated and chain- 



