Monad ilia.] the ixfusoria. 101 



ill the water ; and from Polytoina, l)y never appearing in 

 clusters whilst undergoing self-division. 



37- Glenomorum t'uigens. The green Glenomorum. — 

 This creature has a fusiform body, which is of a beautiful 

 green colour, and three or four times longer than it is 

 broad. Its double proboscis is exceedingly delicate, and 

 about half the length of its body ; within it may be seen 

 some small whitish vesicles, the stomach-cells, and also 

 some minute granvdes, which give rise to the green colour, 

 and may be considered as ova. About the centre of the 

 body is a large transparent colourless organ, which Ehren- 

 berg supposes to be of a male sexual nature. The beau- 

 tiful red eye is fixed internally, about one-third from the 

 anterior extremity of the body. These animalcules con- 

 stitute a great portion of the green matter commonly seen 

 on stagnant water, and discovered by Priestley. They 

 appear to be nearly allied to the Cercaria viridis, differing 

 from them only in magnitude, and in the unalterable form 

 of their bodies. Figure 15 represents two clusters; 16, 

 single ones, magnified 250 times; 17? another magnified 

 about 450 diameters. Found plentiful at Hampstead. Size 

 l-3600th to 1-1 700th. 



Genus VII. Doxococcus. The revolving Monad. — The 

 individuals of this genus differ from those of the whole 

 family Monadina by the singularity of their motion, which 

 may be defined to be neither that of swimming nor of 

 rotation, but a sort of rolling over and over. In other 

 particulars they are like the Monads. They have the 

 same unvarying form, and are destitute of the eye, pro- 

 jecting lips, and tail. Their self-division is simple and 

 complete, or they do not divide at all, in which case they 



