BAG is a set of two neurons with ciliated endings, in the head, with elliptical, closed, sheet-like
processes near the cilium, which envelop a piece of hypodermis (figure 1). These endings have
no associated sheath and socket cells and so are not directly attached to the hypodermis. The
cell bodies are situated anterior to the nerve ring, just ventral of lateral, and send processes
anteriorly to the ciliated endings in the head. Posteriorly directed processes enter the nerve ring
from the cell bodies and then run round the ring to the contralateral side near the outside
surface of the neuropile, eventually ending ventrally. The main synaptic output is to RIA (a,
b), RIB (a, c), AVE (c) and RIG (b). There are a few dark-cored vesicles in the synaptic
terminals (a). There is some synaptic input from AIN (*b), RIG (*d) and AQR (*d). BAG has gap junctions with itself, RIR (d) and RIG (*h).
Magnifications: (a, b) x 25500, (c, d) x 12750.
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