Abstract
Although the morphology of the adult stage of the majority of the helminthic parasites of domestic stock is now well known there still remains a considerable amount of work to be done on the larval stages of these worms. Some of the more recent researches on the infective stage of human and other hookworms have shown that a close study of the morphology reveals appreciable differences between the larval stages of closely allied species and that the differences can be used as diagnostic characters.