The ascaridida is an order of nematodes that includes Toxocaracati which is one of the most common parasites of the cat around the world. The ascarids are characterized by being cream-colored, robust, and relatively long as nematodes go, being one to several inches in length. Other characteristics of this group include the presence of three large fleshy lips on the anterior end of the adult worms, and the eggshells produced by the species found in terrestrial hosts typically are thick shelled and very resistant to environmental extremes. The adults of these nematodes are typically found in the small intestine, and it is there that adults of the two most common species in the cat, Toxocaracati and Toxascarisleonina, are found. Both of these species are capable of infecting cats through paratenic hosts, such as mice, where the larvae are found in the musculature. Unfortunately, the dog roundworm, Toxocaracanis, is also capable of persisting in paratenic hosts, and on rare occasions this host can be the cat. One other ascaridid parasite of the cat, Lagochilascaris, is a strange worm that is a rare parasite of extra-intestinal sites in humans. In cats, these worms have been found in the stomach as well as in fistulated abscess in various locations usually with tracts that drain into the gastrointestinal tract so that eggs are passed in the feces.