In which phylum are nerve cells found but nerves are absent?

In coelenterates,the characteristic larva is

Identify the correct features for $Medusa$ and $Polyp$ forms in Phylum $Coelenterata$ $(Cnidaria)$ from the given list:
$I$ - $Sessile$
$II$ - $Umbrella-shaped$
$III$ - $Free-swimming$
$IV$ - $Produced$ $by$ $asexual$ $reproduction$
$V$ - $Cylindrical$
$VI$ - $Produced$ $by$ $sexual$ $reproduction$
$Medusa$ $\quad\quad$ $Polyp$

Hydra is:

Which one of the following animals possesses nerve cells but no nerves?

'Ephyra' is the stage in the life cycle of