THE JELLYFISH AND THEIR ALLIES 



3457 



The air bladder and its comb look like molten silver, adorned with light blue, vio- 

 let, 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 traveler 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 relates that 

 during the first voyage round the world made by the ship Princess Louise, a sailor 

 jumped into the sea to capture a large Physalia. As he seized it, the animal envel- 

 oped him in its long filaments, stinging him so terribly that he cried out for help, 

 and was hardly able to swim back to the ship to let himself be hoisted up. Severe 

 inflammation and fever followed, and his life was for some time despaired of. 



During the Challenger expedition, deep-sea Siphonophora of a remarkable 

 kind were brought to light. The most interesting belonged to a new family, the 

 Auronectidce. The colony, instead of being a long string of individuals, is here 

 'thickened and shortened so as to be oval or round. It consists of a hard, 

 cartilaginous mass, traversed by a close system of branching canals. The upper 

 part of this mass is a large, round, hollow air bladder (p in the figure). This 

 pneumatophore is surrounded by a 

 circle of large, round swimming bells 

 (n), one of which (/) is modified in 

 a remarkable way. It is not, like 

 the rest, quite hollow, but is traversed 

 by a narrow canal attached to its 

 walls by strands of gelatinous tissue. 

 The free end of the canal opens out- 

 ward through a short tube, while its 

 attached end enters the great bladder 

 of the pneumatophore. This specially 

 modified rowing bell has been called 

 the aurophore, since it appears to 

 regulate the quantity of air in the air 

 bladder. In order to sink to a greater 

 depth, the Stephalia has only to con- 

 tract its pneumatophore, discharging 

 the air through the lateral canal. 

 When the animal rises, the aurophore 

 probably secretes a gas which fills the pneumatophore again. The lower end of the 

 colony is occupied by a large feeding or nutritive polyp, and at its sides there 

 are several rows of smaller nutritive polyps (.?), each of which, at its base, carries 

 a capturing filament (/), and at its side grape-like clusters of reproductive 

 bodies. 



The Siphonophora, as a rule, require frequent changes of depth. It does not 

 appear that exclusively deep-sea forms are to be found in the Mediterranean, but 

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Stephalia (natural size). 



