Volvocina,] THE INFUSORIA. 125 



Animalcules are characterized by being deficient of the tail, 

 but provided with a beautiful red eye, indicating a sensitive 

 system, and a double flagelliform proboscis, for the purpose 

 of locomotion, &c. The shell-like envelope, which bears the 

 form of a little box (urceolus) encloses the creature up to 

 the mouth, and when the young have attained to maturity 

 and self-division is to be completed, it bursts, to set them at 

 liberty. The lorica is with difficulty perceived upon the 

 young ones. 



84. CnL,AMiDOMONA.spulvisculus(Monaspulvisculus > M.) 

 The dust Monad. Body composed of green corpuscles, 

 of an oval form, and included within a box-like shell. 

 Eye brilliant red, and proboscis double. The clusters are 

 globular, and made up of only three or four, or at most 

 eight? Group 52 represents a single one; also a cluster 

 about to separate into five, the latter enclosed in a common 

 envelope. 



These creatures form the larger portion of the green 

 matter which gives colouring to the water contained in 

 water-butts, ponds, and puddles, in the summer and 

 autumn, and especially after a storm. It could hardly fail 

 to have been observed so soon as any of this green water 

 was examined under the microscope. 



Wherever these creatures exist in great quantities, mul- 

 titudes of them die ; their bodies, and the envelopes cast 

 off by the living ones, are decomposed, gaseous matter 

 is generated, which, adhering, causes them to rise to the 

 surface of the water, forming a green stratum upon it. 

 Although the animalcules, and their coverings, when in 

 this state, somewhat resemble Ulvaceae, yet are they easily 

 distinguishable from them by the red speck or eye, which 

 is retained for a considerable time after death, and the new 



