Central canal ( C ; Henle, 1871 ) : The narrow, sometimes occluded part of the ventricles (Hippocrates) that is caudal (Cleland, 1879) to the fourth ventricle (Galen, c177), in the caudal (Cleland, 1879) end of the medulla (Winslow, 1733) and in the spinal cord (Galen, c162-c166). At least the initial rostral (Schulze, 1893) part of the central canal of macrodissected adult animals not including humans was observed in the second century by Galen-see translations by De Lacy (1980, pp. 447, 453), May (1968, p. 416), and Duckworth (1962, p. 14)-and was named such by Henle (1871, p. 42), if not earlier.