Langerhans Lang·er·hans (läng'ər-häns'), Paul. 1847-1888. German pathologist known especially for his histological studies of the skin and pancreas. The islets of Langerhans are named for him.
The retina of Petromyzon was figured and described by langerhans in 1873.
I agree with langerhans in denying the existence of ganglia on the roots of the nerves.