If. W. KING ON POND LIFE FROM THK WKST INDIES. 141 



it to move up and down, sometimes incessantly drawing earthy 

 particles by means of its tail, to fill up vacancies should they 

 occur, or add to its dimensions when required. 



The tabes thus formed are sometimes only three or four 

 times, at others eighteen to twenty times its own length, or 

 even longer. They are composed of fine earthy particles ad- 

 hering without regularity to one another, often with diatoms 

 and flocculent matter entangled among the particles, and pro- 

 bably held together by some viscid secretion of the animal, in- 

 soluble in water. Their forms are varied, often quite straight, 

 at other times curved, some are turned at sharp angles, or 

 carried crossways through other tubes not inhabited. 



In all cases the tubes are constructed to enable the indus- 

 trious creature to swim easily up and down them. Of this they 

 are very particular, any obstruction by bulging out or pressing 

 in occurring by other life coming in contact to damage the 

 tube is at once made right by the Rotifer fixing its claw-like tail 

 or foot to both sides of the tube and jerking backwards and 

 forwards, by so doing again forcing the walls of the tube out- 

 wards or inwards, as the case may require, to their former 

 position. Should some of the small earthy particles have been 

 moved away, the Rotifer will then thrust itself out of its tubular 

 dwelling backwards, with its head inside (and, I believe, fixed 

 with its small horn-like processes), and then draw^ the particles 

 back again in position by means of its claws. 



It is a remarkable power these minute animals have over this 

 forked tail of feeling for and selecting particles suitable to their 

 purpose when the so-called eye-spot is hid and buried in the 

 tube, and therefore rendered useless in this condition for action 

 outside the tube. 



When the tube appears completed and some loose material 

 has been drawn to the openings to close them, the Rotifer may 

 be seen to swim backwards and forwards, coursing regularly 

 along, mostly going the entire length of the tube, though some- 

 times stopping short as if to feed, then turning, will go back 

 again. 



The sense of adaptability in these Rotifers must be largely 

 developed, as they sometimes take possession of vegetable tubes, 

 and adapt them to their requirements by building a wall with 

 small particles of refuse across the tube (see c, c, Fig. 5, PI, 



JouRN. Q. M. C, Series II,, No. 32. 10 



