Anatomy of the cerebral ganglion of the female acanthocephalan, Macracanthorhynchus hirudinaceus

Abstract An atlas of the cerebral ganglion of M. hirudinaceus has been constructed and the cells identified by number. There is a total of eighty‐six cells, three of which are binucleate. These cells (30, 80 and 90) are located in the frontal plane. Most cells give rise to bilateral processes and are organized in such a way that there is an outer coat of somata or cell bodies and a center core or neuropile. Some cell processes are 8 μ in diameter and most exit the ganglion via nerves of the opposite side. The cytoarchitecture of these cells indicates most have perinuclear rings and a well defined nucleolus. However, considerable variation occurs in number and distribution of cytoplasmic granules.