338 Illinois State Laboratory of Natural History. 



VORTICELLA Linn. (Bell Animalcule.) 



Inverted bell-shape, attached singly by a slender pedicel 

 containing a highly contractile central thread ; peristome end 

 usually very wide ; nucleus usually band-like. Many species 

 of this genus were found, but few of them could be deter- 

 mined with any certainty. 



77. V. campanula Ehrbg. 



Found in July among Lemnacece and other vegetation in 

 Quiver Lake and the river, and once again in December in a 

 river towing. 



78. V. microstoma Ehrbg. 



A few were noted in July, taken from among Lemnacece 

 upon the river at E. 



79. V. similis Stokes ('87). 



Common in July on roots of Lemnacece in the very weedy 

 bay of Quiver Lake known as the " Pumpkin Patch." 



CARCHESIUM Ehrbg. 



Animals like Vorticella, but forming tree-like colonies, the 

 individuals borne upon the tips of a single branching stalk, 

 with a contractile central thread. At the forkings of the 

 stems the contractile thread of one branch is continuous with 

 that of the stem below, while that of the other is not con- 

 nected, thus permitting the independent extension and con- 

 traction of the separate zooids. 



80. C. polypinum Linn. 



This was also found on the roots of Lcmnaee<e in the 

 " Pumpkin Patch" in July. The colonies found were rather 

 small. It was not common. 



81. C. lachmanni Kent. 



This species was abundant about the field laboratory in 

 Quiver Lake in May. It was first noticed in some breeding- 

 cages used in rearing aquatic larva?. It multiplies very 

 rapidly in foul or stagnant water. Some were placed in 

 glass jars in the laboratory, and in a few days the entire 

 inner surface of the jars was coated with a dense grayish 

 layer. 



