DISCOPHORA. 79 
CHAPTER VII. 
SUB-CLASS DISCOPHORA. 
THE group of AHydrozoa here spoken of as Dzscophora or 
Meduside comprises most of the familiar organisms known to 
visitors at the sea-side as sea-jellies, jelly-fishes, or sea-nettles ; 
this last name being derived from the power possessed by some 
of them of stinging pretty severely in virtue of the possession of 
numerous thread-cells. Under the name, however, of sea-jellies 
are included a number of large organisms, extremely common 
at certain seasons in our seas, but now known to be properly 
referable to another group of the Hydrozoa (viz., Lucernarida). 
It is these large forms which alone possess any power of sting- 
ing man, and to these the term of “sea-nettles” ought properly 
to be restricted. They are better known under the name of 
“hidden-eyed” Medus@, applied to them by the late Edward 
Forbes. Under the present group of the MWedusid@ are in- 
cluded only a number of small jelly-fishes, found in great abund- 
ance at certain times, floating in the open sea, but nevertheless 
very little known to the general public in consequence of their 
very minute size. These delicate and diminutive organisms 
were originally described by Edward Forbes, for reasons to be 
immediately stated, as the “naked-eyed” Meduse@. It is now 
known, however, that most of these naked-eyed J/eduse@ are in 
reality nothing more than the free-swimming generative buds, 
or medusiform gonophores, produced by budding from so 
many of the other Hydvozoa, and then detached, as we have 
formerly seen, to lead an independent existence. That this is 
their true nature, is shown by the fact that the eggs which they 
produce, develop themselves, not into fresh J/edus@, but into 
various other forms of Hydrozoa, which are fixed or oceanic. 
Under these circumstances, therefore, the naked-eyed Jeduse 
which can be shown to be of this nature, cannot, of course, be 
regarded as distinct animals at all. Still, there remains a con- 
