Polycystina
having as initial skeleton a spicule with a variable number of spines arising
from the two ends of a median bar or from a centre. Spines equal or unequal,
disposed in variable patterns, and usually separated into an apical and
a basal group. Shell usually present, latticed or spongy, or a combination
of both; when multiple, it is usually concentrically disposed, never along
an axis. Median bar or spicule centre located inside the innermost shell,
or quite eccentric in its wall.
Select
a genus name : Acanthocircus
and click below
to go to ......