On the Classification of the Ascabidae. I.— The Systematic value of certain characters of the alimentary canal

Abstract

The great French helminthologist, Dujardin, appears to have been the first to suggest a grouping of the genus “Ascaris” according to the structure of the alimentary canal. As is, unhappily, only too well known to modern helminthologists, little attention was paid to internal structures by the earlier workers, whose numerous descriptions and classifications were based almost entirely upon external characters. It is now recognized that a natural system must be based on a survey of the whole structure of the animal, both external and internal, and a re-examination of many of the older species becomes extremely important.