458 DR. MOXON ON THE ANATOMY OF ROTATORIA. 
be made out; if such a specimen be gently compressed, so as to impede the wavy move- 
ment of the tube, the observation will be more certain ; but absolute demonstration must 
depend on the occurrence of such an act as I have witnessed in three instances, in which 
the creature, by a quick convulsive effort, turned its anterior third inside out, everting 
the whole of the approaches to the gizzard, and then expelled the contents of the gizzard 
through the everted tube (fig. 1* d). The whole proceeding looks much like self-destrue- 
tion, but the animal in allthe cases slowly withdrew the everted parts and reassumed 
its proper shape. Whilst the tube is everted and the ciliated inner side of it has become 
external, the cilia can be very plainly seen vibrating on its then exterior surface (fig. 1° d). 
I have thus fully described this structure, as I believe the employment of a long, lax; 
ciliated tube as an intestinal valve is not on record. A more effective contrivance, and 
one more admirably suited to the wants of the creature, it would be hard to devise. 
The construction and disposition of that portion of the alimentary system which is 
below the gizzard is very constant in all Rotatoria. It has already been well described. 
It is lined throughout with cilia, which, however, are far from constant in their activity. 
It is divided into two parts by a sphincter: of these the upper and larger, called stomach, 
is provided with two follicles, one on each side, which open into the upper part of it; 
the lower and smaller part of it, called intestine, opens either into the contractile 
vesicle, or into the cloaca, in common with that and the ovarian duct. In Euchlanis 
dilatata, where the observation is best made whilst the ereature is turned upon its side, 
there is in the cloaca a sphincter, just below the region where these tubes open into it 
(fig. 7v). I have seen this sphincter do the following service :—the intestine contained 
much fecal matter, and its cilia were motionless, the sphincter of the cloaca closed, and 
then, by the systole of the contractile vesicle (fig. 7 2), the contents of the latter were 
thrown up into the intestine (fig. 7 g); the liquid could be seen to spread up between 
the mass of contents and the intestinal wall, waking the cilia into action: this act was 
repeated several times, and was soon followed by the extrusion of the fiecal matter. 
Whether the fluid was thrown up to wash out the remains of nutriment from the refuse 
of the food, or whether it was a natural enema, to ease the excretion off. the sides of the 
bowel, I cannot say; but, believing the water-system to be excretory, I think the latter 
the most probable reason. 
The so-called water-vascular system is one of the most striking and interesting features 
in the anatomy of the Rotatoria ; yet, at the present time, it is the subject of what I 
cannot help calling a remarkable error regarding its ciliated appendages. 
Its presence has been uniformly denied by all describers to the genera Limnias and 
Floscularia, 
In both these I have had no difficulty in recognizing and carefully examining this 
aysteto. In Limnias it offers nothing worthy of especial notice (fig. 8 &) : but in Flos- 
eularia the tubes and ciliated funnels of the water-vaseular system are very small in 
diameter When compared with the bulk of the creature's body; they are strictly sym 
metrical, and start below from a globular vesicle (fig. 14), which I could never see 
contract, though I have watched it for hours; this vesicle opens by a round orifice, 
situate in the dorsal middle line, at a little distance from the caudal end of the body; 
