62 THE WORLD OF THE SEA. 
They were regarded as microscopic nautili but of a lower deve- 
lopment; but the discovery of some living specimens, and a careful 
examination of their characters, proved that they belonged to a 
HELIXOSTEGA. 
class of animals which had a very much more simple construction 
than the last-named mollusks. 
Dujardin considered them to be infusoria ; other naturalists are 
inclined to place them in alliance with the meduse. Cuvier says 
nothing more about the inhabitants of these shells than that they 
have oblong bodies, surmounted by numerous red_ tentacule. 
ENTOMOSTEGA. 
Modern observers have noted that they are formed of a gelatinous 
substance which fills the chambers of which we have spoken, each 
chamber communicating by pores in its walls. Out of these pores 
issue long and slender capillary filaments, which have no particular 
shape and are always changing. They are like threads of glass 
which extend all round the animal. In some species there are only 
eight or ten of these filaments; in others a much larger number. 
