229 
On a New Melicerta. By Dr. G. T. Hudson. 
even till tlie knob on which the setae are placed comes right down 
to the very base of the antenna. 
When the animal is contracted and shrank down into its sheath, 
the antennae are closely applied to its club-shaped body ; and as it 
rises they slowly rise also from their curved and recumbent position, 
while the action of the transverse muscles at the same time expands 
the animal, and (by forcing its perivisceral fluid into the tubes) 
pushes up the setae-bearing knob till the antenna attains its full 
length. This too is almost always the signal for the unfolding of 
the trochal disk. 
The internal organs are so like those of M. ringens that there 
is hut little to say of them. One point however is worth noticing, 
and that is that I have no doubt that the lower stomach acts in this 
animal as the contractile vesicle. 
The majority of rotifers, as is well known, have twisted tubes 
on each side of their bodies carrying ciliated tags, and these tubes 
generally open into a contractile vesicle which in its turn empties 
itself into the cloaca, or into the lower stomach. But some 
rotifers have no contractile vesicle ; and some, as Pterodina, have 
apparently the ends of the tubes enlarged in lieu of it. It has been 
made out in one or two cases that where there is no contractile 
vesicle the tubes open directly into the cloaca ; but in the case of 
M. tyro I distinctly saw on two occasions the empty lower stomach 
expand and become very transparent, just as the contractile vesicle 
does periodically; and after being slowly dilated to its utmost 
expansion, it shot out its perfectly fluid contents through the vent. 
While this was going on the passage from the upper to the 
lower stomach appeared to he completely closed. 
Of course it is impossible to see any fluid pass from the tortuous 
tubes into the lower stomach, nor indeed did I quite succeed in 
satisfying myself that I had seen their points of junction with it : 
hut the tubes themselves are readily seen, and so with a little care in 
focussing are the ciliated tags, of which I counted five on either 
side. 
My specimens all died before I had finished my investigations, 
hut Mr. Bolton of Stourbridge most kindly came to the rescue and 
sent me a small piece of Anacharis on which there were nearly a 
score of the new rotifers, most of which had bred in his own tank. 
There were also many eggs attached to them, and I eagerly 
scrutinized all the specimens in the hope of finding eggs whose size 
and shape might denote males. While doing this I saw a young 
male rotifer circle round the female which I had under observation, 
and then dart off in their usual headlong fashion. This was too 
great a prize to he willingly surrendered, so I removed the zoophyte 
trough from the stage, and with eye-lens and pipette explored the 
vast Atlantic in which the little creature was disporting itself, till 
