Vorticellina.l tNPTtsonTAt antm-alcules. 523 



seminal gland is long, non-articnlatcd, 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 thit? 

 species is more of a yellowish white than the preceding. Found 

 upon decaying reeds, leaves, &c. Common, in summer, in standing 

 water on stones. Length l-140th; extended, l-24th. 



Stentok casruleus. — Resembles, exteriorly, the two preceding species, 

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

 seen in figs. 235 and 236, (plate 5). It is trumpet- shaped when 

 extended, ovoid when contracted ; white or semi-transparent, except 

 when coloured by food. The lateral crest and frontal wreath, or 

 cro^vn of cilia, are continuous. When kept in glass vessels they often 

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

 been observed. They are best examined under a microscope, 

 when placed in a large live-box. A magnifying power of 100 dia- 

 meters is sufficient. Found amongst Yauchcria. Length l-480th. 



S. pohjmorplius resembles the preceding in form. Ova of a beau- 

 tiful green coloiu' ; gland articulated and chain- like ; lateral crest 

 indistinct; frontal wreath of ciUa interrupted. This species will 

 not receive indigo readily. Transverse self-division has been ob- 

 served. Found upon stones, decayed sticks, and leaves, in standing 

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



S. igneus. — Is less than the preceding ; the ova are of a yellowish 

 green colour ; skin bright yellow or vermilion ; gland spherical ; 

 lateral plume or crest absent ; frontal wreath of cilia interrupted. 

 Found by Ehrenberg upon the water violet (Hottonia palustris). 

 Length l-72nd. 



S. niger {Vartieella nigra, M.) — Small, of a dark brownish-yellow 

 or blackish colour ; ova olive coloured ; gland spherical ; lateral crest 

 absent ; frontal ^\Teath of cilia continuous. This species is often so 

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

 hue, resembling an infusion of coiFee. The swimming movement 

 of this species is readily seen (as in the others) ^vith the naked eye. 

 Size l-96th. 



Genus TEicnoDnsTA. The urn Animalcules. — Vorticellina destitute 

 both of tail and pedicle. They are distinguished from the preccdiug 



M M 2 



