136 THE OCEAN WORLD. 
play the part of the fisherman who throws his line, furnished with 
baited hooks, withdrawing it when he feels a nibble, and throwing 
again when he discovers his disappointment. These efforts con- 
tinued in full vigour for two or three days, and I have succeeded 
sometimes in feeding them with the small crustaceans which swarm 
on our coasts.” 
Of the Zersonnel of these colonies a few words will not be mis- 
placed. The common axis of the Aga/ma is a hollow muscular tube, 
the length of which may be three feet, and its breadth an eighth or 
tenth of an inch; it is traversed by a double current of a granular 
fluid ; at its summit is the aérial vesicle ; beneath are the swimming- 
bladders. These are disposed along the trunk in a double series, 
attaining sometimes the number of sixty ; their structure is analogous 
to the same organs in Physophora. 
In examining the posterior portion of the trunk, traversing polyps 
are observed at intervals, whose base is surrounded by a cluster of 
reddish grains, each of which is armed with a me, and, with its 
surrounding filament, terminating in a tendril of a red vermilion 
colour, which is a perfect arsenal of offensive and defensive arms. 
There we find “ saéres”’ of divers sizes, and poniards of various forms, 
the whole constituting a truly formidable stinging apparatus. 
Those warlike engines, those arms of attack and defence with 
which man surrounds himself, Nature has freely bestowed on these 
little creatures with which the ocean swarms in some places. It 
might be said that, after having created these graceful creatures to 
ornament and decorate the depths of the ocean, the Creator was so 
pleased with his work that he furnished them with arms for their 
protection and defence against all attacks from without. 
The family PAysophoring includes several genera. Fig. 46 is a 
representation of Physophora hydrostatica, after M. Vogt’s Memoir. 
We see that the animal is composed of a slender vertical axis, 
terminating in an aérial vesicle or float, carrying laterally certain 
vesicles, known as swimming-bladders, which terminate in a bundle 
of whitish slender threads. 
The aérial vesicle is brilliant and silvery, punctured with red 
spots. The swimming-bladders are encased in transparent and 
somewhat cartilaginous capsules, which are continued into the 
common median trunk, the latter being rose-coloured, hollow, and 
very contractile ; in short, it presents very delicate muscular fibres, 
which expand themselves on the external surface of each capsule, 
and is closed on all sides. 
The swimming-bladders are of a glass-like transparency, and of a 
