Bags for endoscopic retrieval of tissue; Endoscopes; Endoscopes for diagnostic use; Endoscopes for medical use; Endoscopes for surgical use; Endoscopes for therapeutic use; Endoscopic apparatus; Medical apparatus for use in endoscopy; Operating instruments for use with medical endoscopes; Operating instruments for use with surgical endoscopes; Optical apparatus for medical endoscopy; Optical instruments for medical endoscopy; Rigid endoscopes