Volvocina.] THE INFUSORIA. 115 



but in most of the species the green ova hide them from 

 our sight. The propagative apparatus is evident in all the 

 genera, with the exception of the Uroglena, under the form 

 of ova grains, one or two round glands, and a contractile 

 bladder. 



The family is disposed into ten genera : five are furnished 

 with the visual organ, situated at the anterior part of the 

 body, and five are not. In the former, a sensitive system 

 is consequently presumed. 



The following is an analysis of the family, and arrange- 

 ment of the genera : — 



/ ( vibrating ) „ 



/ I proboscis absent J .' & ■ 

 Lorica box-like •{ 



Lorica singled vibrating | p^.^j^nna. 



Tail J V proboscis present ) 

 absent I I 



I clusters tabulated or in plates Gonium. 



\Lorica double Syncrypta. 



'"^ Tail present Synura. 



tail present tTrog 



Self-division both 



equal and perfect 1 ( proboscis single ... Eudorina. 



(no internal globes) ( tail absent ... -j 



, proboscis double ... Chlamidomonas. 



Self-division unequal f Proboscis single Sphaerosira. 



(fonniug internal -l 



globes) 1^ proboscis double Volvox. 



Genus XVI. Gyges. The ring Animalcule is cha- 

 racterized by the species being deficient of the eye, tail, 

 and vibrating filiform proboscis. The lorica is of a simple 

 box-hke form (urceolus). We know but little of their 

 organization, as not even the nutritive apparatus has been 

 observed ; and were it not that some slight spontaneous 

 motion of the body is perceptible, when it is surrounded 

 with a coloured fluid, it would seem that they were wanting 

 in all the certain characteristics of an animal. Two species 



I 2 



