THE MEDUS&. 145 
physalia the natatory organs are passive. When the sea is calm 
they may be seen floating upon its surface; their body is a cylin- 
drical bladder, dilated in the middle, bearing a fancied resemblance 
to the hull of a ship. Their colour is purple, shading off to blue. 
Beneath the vessel are a great number of fleshy tentacles, cylindrical 
and twisted, which hang down perpendicularly, like tassels of blue 
silk. The central members of this bunch have attached to them 
PHYSALIA. 
(Physalia Antarctica.) 
fine, movable, contractile threads, which hang down many feet into 
the water. These threads are studded with starry pearls of the 
colour of indigo, which form borders, and spirals, and zigzags of 
an elegance hardly to be conceived. “These galleys,’ says Lesson, 
“move along painted with the richest hues. The upper part is in- 
flated with air, often to a size equal to the rest of the body, and 
thus forms a sail, by which they are blown over the waters. This 
white expansion is often tinted with blue, and shaded with pur- 
ple and violet ; a frill at its ridge is of bright carmine, forming a 
K 
