108 Marvels of Pond-Life. 



Dictionary ' they are said to belong to tlie Vorticella 

 family, which has already given us several beautiful 

 objects, and possess a marvellous power of changing 

 their shape. It is, however, better to follow Stein, who 

 separates them from the Vorticellids and ranges them 

 in his order Heterotricha, as they have two distinct 

 sets of cilia, small ones covering the body and the 

 larger ones round the mouth. Those before us are 

 named after this property Stentor polymorphus ,^ or 

 Many-shaped Stent or s, and owe their exquisite tint to 

 numberless green vesicles, or small cavities filled with 

 colouring matter like that of plants. This, however, is 

 not essential to the species which may often be found 

 of other hues. In size this Stentor varies from a 

 hundred and twentieth to one twenty-fourth of an 

 inch. It is entirely covered with fine cilia, disposed in 

 longitudinal rows, and round the head is a spiral 

 wreath of larger and very conspicuous cilia leading to 

 the mouth. 



Having observed the abundance of these creatures, a 

 few small branches to which they were appended, were 

 placed in the glass trough, and viewed with powers of 

 sixty and one hundred linear. Some had tumbled 

 down as shapeless lumps, others presented broad 

 funnel-shaped bodies ; while others stretched themselves 

 to great length like the long, narrow post-horns which 

 still wake the echoes of a few old-fashioned towns. 

 The ciliary motion of the elegant wreath was active 

 and rapid, causing quite a stir among all the little 

 particles, alive and dead ; and when the right sort of 



* See Frontispiece. 



