ROTIFERA. 33 



sulphuric acid on the one side, and by the potash on the other. The 

 apparatus was then exposed to the influence of summer light and 

 heat ; at the same time there was placed near it an open vessel, with 

 the same substances that had been introduced into the flask, and also 

 after having subjected them to a boiling temperature. In order to 

 renew constantly the air within the flask, the experimentor sucked with 

 his mouth several times a day the open end of the apparatus, filled 

 with the solution of potash, by which process the air entered his 

 mouth from the flask through the caustic liquid, and the atmospheric 

 air from without entered the flask through the sulphuric acid. The 

 air was of course not at all altered in its composition by passing 

 through the sulphuric acid in the flask ; but all the portions of living 

 matter, or of matter capable of becoming animated, were taken up by 

 the sulphuric acid and destroyed. From the 28th of May until the 

 beginning of August, Professor Schulze continued uninterruptedly 

 the renewal of the air in the flask, without being able, by the aid of 

 the microscope, to discover any living animal or vegetable substance; 

 although, during the whole of the time, observations were made 

 almost daily on the edge of the liquid ; and when, at last, the Pro- 

 fessor separated the different parts of the apparatus, he could not 

 find in the whole liquid the slightest trace o^ Infusoria or Confervm, 

 or of mould; but all three presented themselves in great abundance 

 a few days after he had left the flask standing open. The vessel 

 which he placed near the apparatus contained on the following day 

 Vihriones and Monads, to which were soon added larger Polygastric 

 Infusoria, and afterwards Rotifera.* To the organisation of this 

 higher form of Infusoria, which are always the last to appear in 

 infusions, I now proceed. 



The Rotifera are so called on account of the aggregation of their 

 cilia into circular or semicircular groups upon lobes or processes of 

 the head, which resemble rudiments of the ciliated tentacles of the 

 higher orCiliobrachiate Polypes.-j- By the vibration of these cilia, which 

 occasions the appearance of little wheels in rapid motion, strong cur- 

 rents are produced in the surrounding water, and they thus serve as 

 the instruments for locomotion and the prehension of food. The body 

 in the Rotifera is more or less elongated or vermiform. It is provided, 

 at its posterior extremity, with a pair of slender and pointed claspers, 

 protected by a sheath, into which they can be retracted when not in 



* This experiment was quoted from the Edinburgh New Philosophical Journal. 

 Vol. xxiii. p. 165. PI. 1. fig- 2. gives a representation of the simple and effectual 

 apparatus devised by Prof. Schulze. W.W. C. 



t Ehrenberg remarks that tlie Rotifera are " Bryozoa without tlie power of pro- 

 pagating by gemmation." — Die Infusionsihierchen, fol. 1838, p. 384. 



D 



