2 Dr. A. Krohn on the Structure and 
In May of the present year, during the last two weeks of my 
stay in Nice, I had daily opportunities of examining Hleutheria. 
It occurs there exclusively upon a delicate confervoid Alga, close 
to the sea-shore, along that part which bears the name of Boule- 
vard de l’Impératrice. It is to these observations that I am in- 
debted for being enabled to fill up many gaps left in the me- 
moirs of both my predecessors. 
The Eleutheria which is to be met with at Nice agrees in all 
respects with that living on the Devonshire coast. As already 
indicated by Hincks, it is distinguished from the EZ. dichotoma, 
discovered near the Chausey Islands, by having only one of the 
two branches into which each of the six arms divides furnished 
with a button, abundantly beset with nematocysts; whilst in 
E. dichotoma, both branches of the arms are provided with a 
button (pelote) of this kind, In size, the Eleutheria found at 
Nice agrees with E. dichotoma, measuring, when the arms are 
fully extended, 1°25 to 1:50 mill., of which 0°50 mill. goes to the 
diameter of the body. 
When a lively specimen of the Eleutheria is placed in a drop 
of sea water on the object-plate, and examined under a suitable 
magnifying power, it is seen immediately to move from the place 
by means of its arms. We are thus convinced that the progres- 
sion is effected exclusively by the branches of the arms which are 
furnished at their extremities with a sucker-like disk, which now 
adhere to the support and then again quit their hold in variously 
alternating order. The knobbed branches of the arms are only 
seen curving to and fro. If, after a little time, the animal has 
attached itself by all its arms, and remains for a time in this 
condition, the branches furnished with an urticating button are 
seen to extend themselves horizontally outwards, above the at- 
tached branches on which the body rests as on so many feet, so 
that they now look like direct continuations of the main stems 
of the arms. The little animal then, to borrow a perfectly suit- 
able comparison of Mr. Hincks, has the appearance of a y 
minute Star-fish. If it be now detached from the object-plate 
by means of needles, and turned over so that the buccal orifice 
is directed towards the observer, it endeavours to get out of this 
uncomfortable position, by bending the sucking-branch of one 
or more of the arms towards the supporting surface, in order to 
attach itself thereby. If it succeed in this, it soon contrives to 
to turn itself over and thus regain its previous position. 
Consequently, whether the Hleutheria creeps upon a horizontal 
plane, as in the case just cited, or, as in nature, upon the above- 
mentioned Alga, which ramifies in every direction, the surface 
of the body in which the mouth is pierced is always turned to- 
wards its support. This surface is therefore to be indicated as 
