Key to genera of CUCULLANIDAE

1 Mouth markedly inclined dorsally; cuticular lining of oesophastom consisting of complex set of thickened cuticularized pieces separated by sutures; cuticularized frame around mouth opening absent................................ Truttaedacnitis

- Mouth opening perpendicular to body axis or slightly inclined dorsally; cuticularized plates of oesophastom few in number and separated by simple Y-shaped sutures; mouth opening supported by peribuccal cuticularized frame to which are joined some

cuticularized pieces inserted into adjacent oesophageal muscles............................................... 2 2 Intestinal caecum absent...................................................................... Cucullanus - Intestinal caecum present.............................................................................. 3

3 Intestinal caecum dorsal; pre-cloacal sucker absent.................................................. Dichelyne

- Intestinal caecum ventral; pre-cloacal sucker present.............................................. Cucullanellus