98 THE EOTIFERA. 



external sign of corona : tlie animal tapers to a point in front as well as in roar. It attaches 

 itsolf by the tip of its licad, and then, releasing and shortening its telescopic foot, takes 

 a fresh hold and arches its body like a leech or geometric caterpillar : it then releases the 

 head in its turn, extends its body, and takes hold again. When it wishes to swim, or to 

 feed, the front of tlie head is arched backwards ; and, by the action of the transverse 

 muscles diminishing the visceral cavity and so driving forward the body fluids, the 

 infolded corona is forced out of a puckered slit on the ventral surface, just where the 

 head joins the trunk. As the corona is pushed out, each disk begins to unfold, and its 

 cilia to act ; while at the same time the tapering forepart of the head, or columii, is thro\ni 

 backward, falling on the nock, between the lobes of the corona, nmch as the hood of a cloak 

 falls upon a lady's slioulders, when it has been dropped from her head. The trunk is fre- 

 quently marked with longitudinal furrows, wliich make it difficult to observe the viscera; 

 and in some species it is tinged with reddish yellow, or brown ; while the extremities are 

 usually free from colour. The penultimate joint of the telescopic foot, in every species 

 but one, carries a pair of soft tapering processes, called spurs, which appear to be useful 

 in giving the Rotiferon a firm hold. The method of attaching itself is this : the three 

 soft toes, rendered sticky by a secretion that exudes from them, are first fastened to the 

 object ; then by the contraction of the longitudinal muscles the last joint is drawn over 

 the toes, and the penultimate joint over the last ; till the penultimate touches aU round 

 the object to which the animal is attached, and the spurs also are brought into contact 

 with it. By this means the Philodinc is securely fastened so as to be able to resist the 

 action of its ciliary wreaths, or to dart back without letting go. 



There are a few points in the internal structure that call for notice. The mastax 

 contains two stout rami, whose appearance is best described by PI. C. III. fig. ti. They 

 are crossed by two or three principal teeth, with sharp points projecting beyond the 

 internal ridges of the rami, and by a multitude of miinite ridges parallel to the teeth. 

 There are also faint indications of the three chitinous loops, attached to each ramus, 

 which are conspicuous in the malleo-ramate type. 



The stomach, intestine and rectum (unlike those of Rhizota] are nearly in a straight 

 line, and the cloaca is situated below the junction of the foot and trunk. The walls of 

 the stomach are unusually thick and absorbent ; and become tinged with coloured food 

 almost immediately after it is eaten. The stomach, when empty, is reduced to a tube of 

 narrow bore, whose end dilates into a globular intestine : there appears to be a sphincter 

 muscle separating the two. 



Gastric glands, though small in size, are usually visible; and foot glands con- 

 stantly. 



The contractile vesicle can be readily seen symmetrically placed in front of the 

 intestine, and though it is difficult to make out the lateral canals, it is generally easy to 

 see some of the vibratile tags. A large triangular nervous ganglion lies ui the neck, its 

 apex pointing forward, and with a red eye on either side of the apex. The dorsal 

 anteima ' is long, tubular, and setigerous ; its terminal part can be withdrawn within the 

 basal, in the same telescopic fashion as that in which the foot is shortened. No ventral 

 antennas have been recorded. 



The reproductive system has been but imperfectly made out. The ovary, with its 

 contained germs, is distinctly visible on either side of the stomach, but no onduct has 

 as yet been detected. 



When a germ becomes developed into an ovnim, it is seen, as it grows, to be gradually 

 separated by a constriction from the rest of tlie ovary, and at last appears to drop off 

 into the body-cavity, in which the young is sonictiiiies completely hatched. 



lioth the living young and the egg have been seen to issue fi-om the cloaca, but it 



' fThe occipital antenna is normally tliice-jointcd, l)ut in some species the third joint is habitually 

 oonoealcd, in others protruded. Yet this, though chiinicteristic, is not invariable. The terminal joint 

 is three-lobed, eacli lobe currying a projecting seta. — V. li. G.J 



