. Comparative studies on certain features of nematodes and their significance. Nematoda. 135] COMPARATIVE STUDIES ON NEMATODES—EETHERINGTON 31 Cephalic Structure in Parasitic Nematodes Symmetrical type of the esophagus What has previously been said regarding the symmetrical factor of the esophagus in free-living nematodes is true of the parasitic forms also, at least those possessing the characteristic triquetrous muscular esophagus. Those nematodes having a capillary esophagus referred to as belonging to the group Trichosyringata comprise a restricted number of genera, among them being Trichi

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. Comparative studies on certain features of nematodes and their significance. Nematoda. 135] COMPARATIVE STUDIES ON NEMATODES—EETHERINGTON 31 Cephalic Structure in Parasitic Nematodes Symmetrical type of the esophagus What has previously been said regarding the symmetrical factor of the esophagus in free-living nematodes is true of the parasitic forms also, at least those possessing the characteristic triquetrous muscular esophagus. Those nematodes having a capillary esophagus referred to as belonging to the group Trichosyringata comprise a restricted number of genera, among them being Trichinella, Trichuris, Trichosomoides, Capillaria, etc. Species belonging to these genera have no free-living larval forms and depend for distribution not upon any migratory effort on their own part but rather upon direct transmission of the embryos or eggs into the new host. Trichina, as is well known, is spread by the ingestion of the uncooked I. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Hetherington, Duncan Charteris, 1895-. [Urbana, University of Illinois]