1887 W. J. Sollas in XXII. 415/1 A transverse muscular sphincter, which defines an outer division or ectochone from an inner or endochone.
1888 G. Rolleston & W. H. Jackson (ed. 2) 795 The..chonae..are divided into an outer part, the ectochone, long and cylindrical, and an inner part, the endochone.