388 Dr. Du Plessis on a new Paludicolous Medusa. 
that of a piece of b centimes. As the size increases, the 
number of tentacles which border the umbrella increases also. 
Colours. The umbrella is transparent and limpid, like cut 
crystal. It is traversed in the form of a cross by four canals 
starting at right angles from the centre of the umbrella, where 
the trunk and stomach are implanted, of which they are the 
continuation. These gastrovascular canals are of an amber- 
yellow or reddish tint, darker or lighter in different specimens ; 
and they are bordered nearly to the margin of the umbrella 
by a very elegant green fringe, folded like a shirt-frill, and 
containing the ova in the females and the spermatozoids in the 
males. 
The four canals reach the margin of the umbrella, and there 
open into a circular canal, which borders its periphery. This 
periphery is not simply sharp-edged, but it bears a veil or 
circular border of a red colour, which, by erecting itself, 
closes a part of the opening of the bell, and bears in the 
centre only an orifice large enough for the passage of the 
trunk. It is a regular mobile diaphragm. Tt is thus reddish 
like the canal. The trunk from which the latter starts is of 
a malachite-green colour, with its quadrate lower extremity 
marked at the four corners with spots of a superb violet. 
These same violet spots also occur in some old examples 
along the folded fringes of the gastrovascular canals and at 
the bottom of the stomach. 
The tentacles, which flow in elegant fringes from the edge 
of the umbrella, are in repose conical and pointed, and all of 
equal length. They are ringed, at equal intervals, by small 
black inflations ; and when they are contracted they, in con¬ 
sequence, appear quite black by the approximation of these 
rings, which are only cushions of urticating batteries which 
the medusa makes use of to strike its prey. When elongated 
these tentacles may exceed ten times the length of the body. 
They then appear grey by the separation of the rings, and, 
from being conical, become cylindrical. 
Between these tentacles at regular intervals there are also 
some little reddish sacs, which contain a pigment spot and 
some crystalline concretions. These marginal corpuscles are 
rudimentary organs of sense. To the naked eye they appear 
like a row of very small reddish pins’ heads. 
From the preceding it will be seen how elegant are the 
form and coloration of the animal. When it springs from the 
bottom, swimming with the rapidity of lightning, the long 
fringes of the umbrella extend through the water, and make 
for it a cloudy train like the tail of a comet. 
Habitat. The canal of the salt-works of Cette, near the 
