OF THE MANDUCATORY ORGANS IN THE CLASS ROTIFERA. 
427 
articulation of the malleus, and is inserted in the wall of the mastax immediately over 
against it. A semi-crescentic band {It) is inserted, by its broad end, into the inferior 
and basal part of the uncus, and by its slender end into the middle of the inner side 
of the manubrium. The former of these {j) may be considered as an extensor, the 
latter (k) as a flexor. A broad and powerful band (/) is inserted along the whole 
inner side of the manubrium, and also apparently into the basal part of the uncus, 
and passes inwards towards the posterior or lobate wall of the mastax ; into which 
it probably merges, as I have not been able to trace its inferior insertion. 
31. The movements of these organs are very complex. The most conspicuous is 
an alternate -approach and recession of the two unci, by a perpendicular motion on 
the hinge-joint. The opposing faces come into successive contact, and bruise down 
the particles of food in the manner of mullers. But a moment’s observation shows 
that there are other movements besides this. The manubria move also at the same 
time ; their free extremities are made to approach each other, as the unci mutually 
recede ; and that with a peculiar twist, which greatly alters the apparent figure of 
these organs. [See figs. 6 to 8 ; of which 6 represents the right manubrium when the 
unci have receded, 8 the same when the unci approach, and 7 an intermediate con- 
dition.] The incus also has considerable motion. Sometimes the fulcrum is elevated 
and the rami depressed, so that the former is invisible: the rami open and shut with 
the working of the mallei, being fastened to them by the strong triangular muscle 
above-mentioned ; but it is also evident that they have a motion of separating and 
closing independent of the mallei, though this is comparatively limited in extent, and 
not very often exercised. Again, when substances are brought into contact with the 
jaws, which, for any reason, are not acceptable, they are thrown up through the buccal 
funnel, by a peculiar scoop-like action of the unci, which is very curious to witness. 
32. I have seen this action many times ; but, in particular, on one occasion, in 
which much intelligence seemed to be displayed. 1 was watching a Brachionus pala 
in water, in which a number of that beautiful, mulberry-like animalcule, Syncrypta 
volvox, were revolving. One or two of these had been devoured, and were very 
visible in the intestinal canal of the Brachioyius, which appeared excited by the enjoy- 
ment to unusual efforts. The mode in which it directed its ciliated flaps towards 
the spot where a Syncrypta was whirling, or suddenly stretched forward to the extent 
of the long foot, as if it would seize the prey, seemed to indicate a perception of its 
presence; as did, still more, the manner in which it depressed the lip-like lobe of the 
rotatory organ on one side, when the prey was in the vortex on that side, and the 
eager haste with which it shrank down into the lorica, the instant the animalcula 
dropped at length into the buccal funnel. Now, however, arose a difliculty ; the 
black, millstone-like unci opened and stretched forward to grasp the little victim ; 
they touched the globular investing case, but could not embrace it. The Brachionus 
redoubled his efforts ; the jaws gaped vigorously, but could only scrape the sides of 
the little globe, which at every touch slipped away, the expanse of the unci being not 
MDCCCLVI. 3 L 
