any of various worms living parasitically in intestines of vertebrates having a retractile proboscis covered with many hooked spines

any of various worms living parasitically in intestines of vertebrates having a retractile proboscis covered with many hooked spines

any of various worms living parasitically in intestines of vertebrates having a retractile proboscis covered with many hooked spines

phylum or class of elongated wormlike parasites that live in the intestines of vertebrates: spiny-headed worms