Sub-family. Trichurinæ, Ransom, 1911.
Male with a single long spicule, with sleeve-like sheath. One ovary. Eggs with an opening at each pole closed by a plug-like operculum. Eggs hatch on being swallowed by a new host. Genera: Trichuris, Capillaria.
Genus. Trichuris, Röderer and Wagler, 1761.
Syn.: Trichocephalus, Goeze, 1782 (nec Trichiurus, L., 1758); Mastigodes, Zeder, 1803.
The anterior part of the body is very long and thread-like; the posterior, much shorter part, is thicker, rounded posteriorly, and the anus is terminal. The males have the posterior extremity spirally rolled; the vulva is situated at the commencement of the posterior part of the body. The Trichocephali live in the large intestine of mammals, the cæcum by predilection; their development is direct, infection occurs through the ingestion of embryo-containing eggs.
Trichuris trichiura, Linnæus, 1761.
Syn.: Trichocephalus trichiurus, L., 1771; Ascaris trichiura, L., 1771; Trichocephalus hominis, Schrank, 1788; Trichocephalus dispar, Rud., 1801.
Fig. 301.—Trichuris trichiura: on the left, male; on the right, female with the anterior extremity embedded in the mucous membrane of the intestine; below, egg.