The Excretory System as a Method of Classification of Digenetic Trematodes

Abstract

The excretory system, particularly the fundamental solenocyte pattern, constitutes a natural system by which not only adults may be related to one another, but by which various larval stages, especially the cercariae and adolescariae, may be placed in major series and even in subfamily and generic groups. This has facilitated the elucidation of life cycles. An illustrated key of representative groups of the Digenea, based primarily on the solenocyte pattern, is given, including the Gasterostoma, ASPIDOGASTRATA (n. n. for Aspidocotylea Mont., 1892) (p.460), Monostomata, Strigeata, Amphistomata, and Distomata. In the suborder Distomata the following families have been studied: Fasciolidae, Echinostomatidae, Dicrocoeliidae, Brachycoeliidae, Plagiorchidae, Allocreadiidae, Heterophyidae, Microphallidae, Lecithodendriidae, Opisthorchidae, and Troglotrematidae. Illustrations show certain spp. (Phyllodistomum spp., Asymphylodora spp., Anchitrema sanguineum, and Cryptocotyle lingua), which must be reallocated to the family group with which their excretory pattern agrees.