Building Apparatus of M. r ingens. By F. A. Bedwell. 215 
the pellet organ specifically ensured, and all in the presence of very 
considerable opposing risks; to understand how these results are 
arrived at is one of the exquisite enjoyments of microscopic research. 
My views differ somewhat from those of Mr. Cuhitt, and will he 
found exhibited (hut diagrammatically only) in PI. CXCV1I., B. The 
first two features that call for attention exist in every wheel-hearing 
rotifer, and are the secondary lips with their respective streams of 
cilia working in opposite directions, and as a clear view of these 
is very useful in assisting us to appreciate a large portion of the 
Botifera as a group, I shall venture to offer the following as a 
mechanical illustration. Conceive a cog-wheel, Fig. 1, working 
from left to right, with great rapidity ; on it, lay two smaller cog- 
w T heels, working the left-hand one from left to right, and the other 
from right to left ; set the apparatus upright in a fluid full of small 
particles, and suppose each wheel to have independent motion 
round a fixed centre, then, if the large wheel had the power 
of drawing from the farther side particles into its teeth and 
jerking them over to the smaller wheels, on this side these 
particles would, if carried by the small wheels, have a tendency 
to meet at the point where the small wheels approach each other, 
and if the small wheels could be made to deliver them at that 
point, the two streams would unite and pass on in a straight 
path down to a receptacle suitably placed for the purpose. 
Now, if for the small wheels we substitute lip - like ditches 
standing out from the main wheel with a Y - shaped transverse 
section, and for the cogs of the larger wheel substitute a rich 
fringe of vibratile cilia, we have the gathering apparatus of ill. 
ringens and of the cognate forms, and if we then fill the Y-shaped 
secondary lips or ditches with cilia, those on our left moving to the 
right, and those on our right moving to the left, we obtain the 
apparatus which ensures the progress to the receptacle of the par- 
ticles so gathered in by the main fringe of cilia. The receptacle 
into which the particles are discharged can be well described by 
likening it to the “ hopper ” of a flour-mill, or to a truncated 
pyramidal figure with its base uppermost, and if we proceed to 
connect such a facial wheel or gathering apparatus to such a 
receptacle as in Fig. 2, then by suitable alterations in the out- 
line and attitude of the facial wheel and the smaller wheels, we 
can obtain the various forms of Melicerta, Limnias, &c. ; but further 
and besides this, if we cut out a triangular piece from the facial 
wheel at the lower portion, and tip the wheel away from the eye 
as on a hinge, and make the two smaller circles coalesce and go 
round the “ hopper,” we obtain, as in Fig. 3, the arrangement seen 
in Conochilus, and have as in Conochilus the sinus or entrance to the 
receptacle in the centre of the facial circle with the principal 
antennas standing out from its surface, and by help of these two 
