Species Organ Haemonchus contortus Abomasum Ascaris ovis Small intestine Strongylus filicollis Small intestine Oesophagostomum columbianum Intestines Uncinaria cernua Small intestine Trichocephalus affins Large intestine Strongylus filaria Bronchi Strongylus rufescens Bronchi and air follicles SWINE Species Organ Ascaris suis Intestines Oesophagostomum dentatum Large intestine Trichocephalus crenatus Large intestine Trichina spiralis Muscles and intestines Strongylus paradoxus Trachea and bronchi Sclerostoma pingencola Renal fat and kidney POULTRY Species Organ Ascaris inflexa Intestine Spiroptera hamulosa Gizzard Heterakis papillosa Caecum Syngamus trachealis Trachea and bronchi INTESTINAL WORMS OF SOLIPEDS.--The large round-worms or ascarides and the sclerostomes are the most injurious intestinal parasites of solipeds. The _A. megalocephala_ or large round-worm is from 5 to 15 inches (12 to 35 cm.) long. It may be present in the double colon in such large numbers as to form an entangled mass that completely fills a portion of the loop in which it is lodged. It may interfere with digestion by obstructing the passage of alimentary matter, and irritating the intestine. The _S. equinum_ and _S. tetracanthum_ are small worms. The former sclerostoma is from 0.6 to 1.5 inches (18 to 35 mm.) long, and the latter is from 0.5 to 0.6 inch (8 to 17 mm.) long. Both sclerostomes attach themselves to the lining membrane of the intestine by their mouth parts, and suck blood. The young _S. equinum_ may live in tumor-like cysts that they cause to form in the lining membrane of the intestine. The young worm may penetrate the wall of a small blood-vessel as well, and drift into a large vessel, where it may become lodged and undergo partial development. The irritation to the blood-vessel results in an inflammation and dilation of the vessel wall. This is termed verminous aneurism. A portion of the fibrin-like lining of the aneurism may flake off and drift along in the blood stream, until finally a vessel that is too small for the floating particle or embolus to pass through is reached. The vessel is then plugged or a thrombus is formed. If the vessel involved by the thrombus happens to be a mesenteric vessel, then a loop of intestine has its blood supply cut off, and colicky pains result. Such colics are dangerous, and may terminate fatally. Intestinal obstruction, thrombo-embolic colics, unthriftiness and a weakened, anaemic condition may be caused by intestinal worms.