THE ROMANCE OF NATURAL HISTORY. 



The open mouth, studded round with a wreath of 

 vigorous cilia in rapid rotatory motion, strikes us 

 with a pleased surprise. The cilia are seen, like 

 hooks, at those parts of the circle, which in per- 

 spective are brought in or near the line of vision, 

 either turned outward or inward according as 

 their motion is more or less rapid ; the other parts 

 of the wreath being visible only as a thin film 

 along the line of their points, and like little teeth 

 at their bases. The obscure semi-transparency of 

 the texture of the animal renders it very difficult 

 to discern the form of the trumpet-outline satis- 

 factorily ; at one time it appears as if circular, 

 but with a large round piece cut out of one side ; 

 which yet has a thin filmy edge, as if the hiatus 

 were covered by a transparent membrane. Then 

 perhaps the mouth is turned slightly towards the 

 eye, and this hiatus is no longer discernible any- 

 where, but one part of the margin is rolled in- 

 wards spirally, but how the other part joins this 

 it is difficult to see. Then suddenly the orifice 

 appears again, but as a large round hole cut out 

 of the side, with the margin quite entire above it ; 

 then in a moment this aperture is seen rapidly to 

 contract, and close up to a point. But all these 

 appearances, — the mystery of which so greatly 

 heightens the interest of these creatures to a 

 young observer, — seem to depend on the presence 

 of a contractile bladder which alternately fills 

 and empties itself, and, when distended, frequently 

 displaces the coloured parenchyma or flesh, to 

 such a degree that only the thinnest film of trans- 

 parent skin bounds it externally. 



The tuft of needle-like leaves, too, is full of life. 

 To the outer ones are clinging multitudes of 

 Diatoms in fans and fantastic chains ; and multi- 

 tudes more of single ones are sprawling about the 

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