The Cerebral Neurosecretory System, Secretory End-Foot System and Infracerebral Gland-a Probable Neuroendocrine Complex inNephtys(Annelida; Polychaeta)

Secretory end-feet, extracerebral cells, and cerebral sense organs in certain limicole oligochaete annelids

Secretory end-feet (or SEF) systems are present in Limnodrilus and Stylodrilus but are less highly organized than those of polychaetes. SEF contain secretory vesicles and abundant mitochondria. Typical neurosecretory terminals are not found within the brain although "neurosecretory" perikarya are present in all four species studied. In Limnodrilus, Stylodrilus and Enchytraeus extracerebral cells, of probable neurosecretory function, are invested by the pericapsular epithelium. Characteristically such cells bear several cilia. In these species and in Stylaria a pair of sensory cell groups is located anteriorly within the brain. These cells are ciliated but lack associated supporting cells.