C. cornu (Zeder, 1800)

Type host. Gray heron, Ardea cinerea Linnaeus ( Ciconiiformes: Ardeidae).

Type locality. Europe; specific type locality unknown.

Remarks. This species was originally listed as Distoma cornu Zeder, 1800 . It was considered to be Monostoma cornu (Zeder, 1800) (= Monostome cornu) and Amphistoma cornu (Rudolphi, 1809) by Dujardin (1845); however, it was incompletely described by Zeder (1800) and Rudolphi (1809), and only briefly redescribed by Dujardin (1845). There is not enough information available beyond body size to effectively delineate this species and in our opinion, this species should be considered a species inquirenda; it was not included in the key to species provided below.