2 Transactions of the Society. 



named Melicerta tubicolaria ; as I have now little doubt, in spite 

 of the errors in his figures and description, that this was the rotifer 

 out of which Ehrenberg framed his genus Tubicolaria. 



Nothing can be more irregular than the shapes of the homes 

 in which these creatures dwell. They are fluffy masses of a 

 substance secreted by the animal itself, and fortified by random 

 gatherings of material thrown down on them by the action of the 

 ciliary disk. Like those of all the tube-making rotifers, they have 

 only a small cylindrical passage down their centre, up and down 

 which the animal moves, and the material of which they are com- 

 posed is continuous from the rotifer right out to the surface. By 

 transmitted light they appear to be hollow ; but this is not the 

 case, and the dark-field illumination will generally enable the 

 observer to trace the delicate material everywhere from the outer 

 surface to the animal within. In Floscularia camjpanulata I have 

 seen the young newly-hatched male bore his way with his long 

 cilia from the side of his mother right out of her case ; and I have 

 also seen it die in the attempt. The most remarkable thing about 

 (Ecistes umhella is its disk, which is so strengthened by ribs across 

 it in various directions, that it looks somewhat like an odd kind of 

 umbrella. Two of these thickenings are very broad, and run 

 across, as shown in the figure, from the ventral to the dorsal side of 

 the disk. When the rotifer closes its disk, it naturally folds it so 

 as to bring these stouter portions together, the thinner parts being 

 folded within them; and, in consequence, it often has an odd 

 square look about its head, that I have never seen in any other 

 species of OEcistes. But this strengthening of the disk is not 

 peculiar to it. The common (Ecistes crijstallinus has precisely the 

 same thing, only on a much smaller scale (as may be seen in the 

 Plate, Fig. 3), and similar thickenings are visible in CE. pilula. 



In (E. umhella there is on either side of the disk a branched 

 rib like a gusset; but the whole structure must be viewed in 

 various directions and by different modes of illumination to get a 

 clear idea of it. The central ribs, when the disk is viewed edge- 

 ways, are clearly seen to project above its surface a little. 



My friend Mr. A. W. Wills found this rotifer in one of the 

 ponds of Sutton Park, and exhibited some specimens in October at 

 a meeting of the Birmingham Natural History Society. Mr. 

 Wills has figured and described it in the December number of the 

 ' Midland Naturalist,' adding to his interesting remarks some accurate 

 measurements of a full-grown individual. From these it will be 

 seen that CE. umhella is much larger than (E. crystallinus, and 

 about twice as large as (E. pilula. On a piece of alga which 

 Mr. Wills has just sent me, the two species can be seen side by 

 side, and form a very pretty picture. They have been living in 

 Mr. Wills' tank, and have come to me in excellent condition in 



