488 CLASS ECHINODERMATA. 
nated in a point, and has eight lines of ciliz. Alcinoe ver- 
miculata, Rang. 
OcyYROE, id., have the same sort of body with four ranges of 
cilie, but without ribs; they have also similar wings, each 
furnished at the base with two ciliated points. Ocyroé ma- 
culata, id., &c. 
It is also near Beroe that we should place 
CESTUM, Lesueur, 
A very long gelatinous ribbon, one of the edges of which is 
furnished with a double range of ciliz. The inferior one has 
some also, but smaller, and less numerous. It is at the middle 
of the inferior margin, that the mouth is situated; a large 
aperture which leads into a stomach, pierced through the 
breadth of the ribbon, and proceeding to a very small anus. 
From the extremity near the anus, proceed some vessels, which 
extend to the two extremities of the ribbon. At the sides of 
the mouth two sacs open, which are probably the ovaries. 
This animal may be compared to a callianira with two ribs, 
and whose wings were excessively prolonged. 
The only known species, 
Cestum veneris, Lesueur. Nouv. Bull. des Sc. June 18138. 
pl. v. f. 1., is from the Mediterranean. Its length, or rather 
its breadth, is more than five feet; its height, two inches. It 
is preserved entire with great difficulty. 
The two following genera, which have also been united to 
the medusz, might form a small family in this order, in con- 
sequence of the internal cartilage which supports the gelati- 
nous substance of the body. 
PorPITA, Lam., 
Have this circular cartilage, and its surface marked with 
concentric striz, crossing with radiating strie. At the 
upper face it is clothed only with a slender membrane, which 
