- Nervous system in Nematodes: Four peripheral nerves run the length of the body on the dorsal,
ventral and lateral surfaces. The nervous system is also the only place in the nematode body that
contains cilia, which are all non-motile and with a sensory function. - Nervous system in Molluscs: Nervous system of snails, like that of all molluscs, is basically
different from vertebrate nervous systems. Molluscs, with the exception of the most highly
developed cephalopods, have no brain in the strict sense of the word. As a remainder of the rope
ladder nervous system, most ganglia come in pairs. - Nervous system in Annelida: The basic annelid nervous system consists of a single or double
nerve cord running along the ventral side of the body with an enlarged region (ganglion) in each
segment. Active annelids, such as the earthworm, have larger ganglia in the head region that serve
as simple “brain”.
The nerve cord originates at the head end of annelid worm, a region known as the cerebral ganglion- that’s the annelid version of a brain.
greg delong
(Greg DeLong)
#1