The presence of a special sense organ,the $statocyst$,at the opposite end of the mouth (aboral end) is a characteristic of:

Identify the given organism.

Write the general characteristics of the phylum Ctenophora.

Identify the phylum which shows the following characteristics:
$1$. Animals are exclusively marine,radially symmetrical,and diploblastic.
$2$. Body bears eight external rows of ciliated comb plates which help in locomotion.
$3$. Digestion is both extracellular and intracellular.
$4$. Reproduction is only by sexual means.

Biradial symmetry and lack of cnidoblasts are the characteristics of

Biradial symmetry and lack of cnidoblasts are the characteristics of