THE VICTORIAN NATURALIST. 103 



includes all those which build a sort of house, more or less in the 

 shape of a tube. They are classed as Rhizota (rooted). After 

 once taking their place they never remove. The tube has a 

 gelatinous sheath as its basis. These householders, which are all 

 females, may be abundant on our weed. Yellowish-brown tubes 

 dotted here and there announce the presence of Melicerta 

 ringens, probably the first favourite amongst Rotifers, and al- 

 most too well known to need description. Many of the tubes 

 may be empty, but presently we see slowly emerging from one a 

 pair of long antennae, and perhaps two tiny hooks ; a wrinkled 

 mass follows, and soon discloses the elaborate and beautiful 

 head of the animal. Four elegantly curved lobes are unfolded 

 in shape like petals of a flower. Fringing their long and sinuous 

 outline we see the principal wreath of strong cilia, suggesting by 

 their unvarying movement, a running endless chain. There are 

 probably few lovers of microscopic life who have not spent many 

 hours in the contemplation of this striking spectacle. Parallel 

 (for the most part) with the principal wreath, separated by a 

 groove, runs a secondary line of shorter and slighter cilia. The 

 building operations of Melicerta are most interesting, and may 

 be shortly described. Particles of floating matter, attracted in 

 abundance by the action of the principal wreath, are hurried 

 along the groove to the buccal funnel. Here they are parted : 

 some swallowed as food ; others borne over a projection, known 

 as the chin, into a small hollow — the ciliated cup. As they 

 gradually collect in this they are whirled round, mixed with some 

 binding secretion, and assume a yellowish colour. In three or 

 four minutes the animal has thus completed one of the pellets 

 with which it builds its tubular house. Watching closely, we may 

 now see the head suddenly plunged down, and the pellet 

 deposited on a previously selected part of the tube's edge. As 

 many as 6,000 pellets have been estimated to exist in a very large 

 Melicerta tube. Allowing three minutes as the time requisite to 

 make and lay each of these, the number mentioned would 

 represent twenty-five days' incessant work at twelve hours a day. 

 Close by we observe a very different tube — dark, granular, and 

 slightly narrowing downwards. Its owner, Limnias ceratophylli, 

 seems to be more sociable than Melicerta. Hence we frequently 

 find six or a dozen of these in near proximity. The animal 

 displays a long and somewhat narrow corona, reminding us of two 

 incomplete circles connected by a concave curve. It shows the 

 principal and secondary wreaths to great perfection. The cilia 

 can easily be traced right down the buccal funnel. The antennre 

 are much shorter than those of Melicerta. In the early life of 

 Limnias ceratoj)hylli its tube is transparent, and the long, thick, 

 wrinkled foot, which is so common in this family, is clearly shown ; 

 later on the granular accretions outside the tube render it opaque. 

 In both Limnias and Melicerta the moving trophi form a very 



