Marvels of Pond-Life. 



47 



is drawn in. As this contraction takes place, two 

 apparently elastic bands, to which the ciliary lobes are 

 attached, are bent downwards, till they look like the C 

 springs behind a gentleman's carriage ; and they regain 

 their former position of slight curvature, when the cilia 

 are again thrust out. 



Pterodina patina — tail-foot. 



The gizzard is three-lobed, and curiously grasped by 

 forked expansions of the handles of the hammers. The 

 tail, or tail-foot, can be withdrawn or thrust out at the 

 will of the creature ; and when in a good position for 

 observation, a slight additional pressure will keep it so 

 for examination. Delicate muscular longitudinal bands, 

 forked towards the end of their course, supply the means 

 of performing some of its motions, and one, or perhaps 

 two, spiral threads extend through the upper half of its 

 length, and either act as muscles, or as elastic springs for 

 its extension. The intestines and other viscera are 

 clearly exhibited, and a strong ciliary action conducts 

 the food to the gizzard-mouth. 



To return to the tail. One spiral fibre is easily dis- 



