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2)ip0 into m^ aquarium* 



By the Rev. William Spiers, M.A., F.G.S., F.R.M.S. 



Part III. 



THE most beautiful of the Rotifers, or wheel-animalcules, are 

 certainly those which are fixed or sessile. These have 

 important home duties to perform, with which the roving 

 life of Rotifer vulgaris would be altogether incompatible. Of this 

 group the most common are Melicerta rijigens, whose wonderful 

 tower of gem-like bricks or pellets every microscopist has gazed 

 upon with delight ; Flosciilaria ornata, so well described and 

 beautifully illustrated in Mr. Gosse's " Tenby " ; F. cornuta^ 

 which, like its congener, F. ornafa, constructs an elegant trans- 

 parent tube or flask ; and Sfephanoceros Eichornii, the garlanded 

 rotifer. 



Familiar as these are to most students of ])ond life, it is 

 astonishing how much there is yet to discover concerning their 

 habits and modes of existence. Few men have made these 

 creatures a longer or more accurate study than Dr. C. T. Hudson, 

 the present President of the Microscopical Society, and yet in a 

 recent address he remarked concerning Melicerta ringejis, the 

 commonest of them all : " No one has ever had the patience to 

 watch the animal from its birth to its death ; to find out its 

 ordinary length of life, the time that it takes to reach its full 

 growth, the period that elapses between its full growth and death, 

 or, indeed, if there be such a period. And yet even these are 

 points which are well worth the settling. For if Melicerta reaches 

 its full growth any considerable time before the termination of its 

 life, it would seem probable that, owing to the constant action of 

 its cilia, it would either raise its tube far above the level of its 

 head, or else be constantly engaged in the absurd performance of 

 making its pellets, and then throwing them away. Who has ever 

 found it in such a condition, or seen it so engaged ? Yet, the 

 uninterrupted action of the pellet cup would turn out the six 

 thousand pellets, which form the largest tube that I am acquainted 

 with, in about eight days, while the animal will live nearly three 

 months in a zoophyte trough, and no doubt much longer in its 

 natural condition." Some other points about which we are 

 ignorant in respect to tube-building rotifers are as to whether the 



