Trachdina.] 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 perceivedjby 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 31 1 

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

 with lemnaand conferva. Length 1-1 40th 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 1-1 20th. 



