Tracfulina.] THE INFUSORIA. 303 



499. Nassula elegans. The elegant Nassula. — Body- 

 cylindrical or oval, slightly attenuated in front, extremities 

 very obtuse. It is white or greenish, spotted with violet 

 vesicles ; digestive cells, containing Chlamidomonas, or 

 other food, may often be observed ; from fifteen to twenty 

 rows of cilii may be seen at one view. The animalcule 

 swims backward and forward, turning upon its longitudinal 

 axis. The mouth is easily perceived^by the currents, when 

 indigo is mixed with the water: it has a circlet containing 

 twenty-six little wands or teeth, which can voluntarily 

 diverge or converge anteriorly. When self-division ensues 

 the large central gland is divided. Figures 310 and 311 

 represent this creature ; the latter is a young one. Found 

 with lemna and conferva. Length 1 -140th to 1-1 20th. 



500. Nassula ornata. The adorned Nassula. — Body 

 ovate or globular, depressed, of a brownish-green colour, 

 variegated with numerous violet vesicles. The posterior 

 part of the body has a small excavation. Ehrenberg says 

 there are from six to eight groups of vesicles, forming a 

 wide circle round the mouth ; these are filled with a violet 

 coloured juice, which is discharged with the excrement, and 

 appears like drops of oil, but soon mixes with and colours 

 the water. Found amongst swimming clusters of oscilla- 

 toria by Ehrenberg. Size to l-96th ; ova l-4800th. 



501. Nassula aurea. The golden-coloured Nassula. — 

 Body ovato-oblong, nearly cylindrical, very obtuse at the 

 extremities. The special organs for digestive juice not 

 distinct. Size I- 120th. 



