1 66 ROTIFERA. PART in. 



transversely striated, which, move the ciliated lobes of 

 the head, push them out and draw them in. From 

 these muscular threads are sent to the different parts 

 of the body, to the mouth especially, two strong- bands, 

 which bend and unbend the joints of the hammer-like 

 jaws. The vigorous motions of the long serpentine 

 foot and the firm hold of its anchors are owing to 

 muscular bands fixed high up on the interior wall of the 

 body, which extend throughout the whole length of the 

 flexible organ. As long as the Brachion is fixed, the 

 vibrations of the cilia on its lobes only produce whirl- 

 pools in the water, but the moment that it lets go its 

 hold, these vibrations, in consequence of the reaction of 

 the water, give the animal both a smooth progressive 

 motion and a rotation round its axis. 



Minute as the Brachionus pala is, it has several organs 

 of sense. A sparkling, ruby-coloured, square eye-speck 

 with a crystalline lens and crimson pigment layer is 

 placed on a wart-like prominence on its back, and this 

 prominence Mr. Gosse believes to be the brain of the 

 animal. In the cleft between the spines and close to 

 the eye-speck are two tubes, one within the other. The 

 innermost tube, which can be protruded and withdrawn, 

 has a bunch of bristles at its extremity that have the 

 sensibility of anteiinse. Nerves from the brain pass into 

 these, to the various organs of the body, and to the 

 lobes on the head. 



The Brachion has no propelling vessel or heart to 

 maintain the circulation of its liquids, but, like the 

 Annelids, a colourless liquid occupies the general cavity 

 between the alimentary canal and the internal wall of 

 the body. It is believed to be connected with nutrition, 

 and is furnished with oxygen by a complicated organism, 

 and is kept in motion by the vibrations of long cilia. 

 The determination of the whole structure and motions 

 of a creature barely visible to the naked eye, is a won- 



