482 
CCELENTERA TES. 
for the nourishment of the whole colony, and are carried to the various parts 
through the axial tube above mentioned. In the illustration, which has been 
chosen on account of its comparative simplicity, no reproductive or egg-bearing 
bells are shown. When present in the Physophora, these appear like clusters of 
grapes; in other genera they are capsules; in others, again, they may be actual 
swimming-bells, which become detached, and lead an 
independent life. This fact is of importance in helping 
us to understand this complicated organism. It shows 
that the Physophora is not a single animal, but a stock 
or colony. Of this there is evidence in the rowing-bells, 
as well as in the two, three, four, or more sucking-tubes, 
with distinct mouths and stomachs. And, lastly, we have 
the reproduction brought about, in some cases, by detached 
jellyfish-like individuals. All the parts of the organism 
form a whole in a physiological sense; they belong to 
one life, and many are so modified as no longer to appear 
as individuals. But, on the other hand, some of them 
are fairly independent, and, when they take the form of 
medusae, they are so highly developed that their individu¬ 
ality is at once manifest. We must, therefore, regard 
a Siphonophore as a colony of highly - modified in¬ 
dividuals, which—owing to the fact that these individuals 
differ greatly in form and function—constitute what is 
termed a “ polymorphous colony.” 
One of the most beautiful and most dangerous of 
the Ccelenterata belongs to the Siphonophora. This is 
the so-called Portuguese man-of-war ( Physalia ), several 
species of which are found in the southern seas. The 
air-bladder at the top of the stem is a large, oval vesicle, 
which projects above the surface, lying horizontally 011 
the water. It is drawn out into two points at opposite 
poles. A comb runs lengthwise and somewhat slantingly 
along the top of it. From its lower side, nutritive polyps, 
feelers on which the genital products develop, and very 
long tentacles hang down side by side below the surface 
of the water. Another strikingly beautiful species found 
in the Mediterranean is P. pelagica. Lesson writes that 
these creatures “ shimmer with the most splendid colouring. 
The air-bladder and its comb look like molten silver, adorned with light blue, 
violet, and purple. The small thickenings on the keel of the comb are of a vivid 
carmine, while the appendages are of a wonderful, delicate, ultramarine blue.” 
The English name is happy, as it indicates the latitude in which the traveller 
from Europe first meets with it, its ship-like appearance on the surface of the 
water, where it uses its comb as a sail to catch the wind, and its ample provision 
of weapons. The tentacles of the Physalia are stiff with batteries of stinging- 
capsules, and those who are careless enough to touch them will repent. Meyen 
Physophora, with two rows 
of swimming bells (nat. size). 
