<p>A) The semi-transparent <i>Leptosynapta clarki</i> is readily found just beneath the sediment during the springtime at False Bay, San Juan Island, WA. Major structures of the echinoderm nervous system are visible through the skin: buccal tentacles (T), circumoral nerve ring (NR), radial nerve cords (RNC) and the dorsal papillae (P). B) FMRFamide-like immunoreactivity was found in processes extending from the nerve ring (NR) into the tentacles (T) (tentacle nerves: TN), in the esophageal region (E) and throughout the body with projections and interneurons (IN) from the radial nerve cords (RNC). C) Histamine-like immunoreactivity was identified in processes extending from the NR and in abundant neurons in the tentacles (T), as well as in processes from the RNCs to sensory-like structures in the papillae (P).</p
