146 PARASITOLOGY. 
tle; they are blood suckers of the worst type, and 
myriads robbing the host of blood cause an un" 
thrifty condition; in calves they cause a stunted 
growth; later anemia, emaciation and possibly death. 
Treatment.—The same as for the Strongylus Con- 
tortus. 
UNcINARIA CERNUA. (Cernuus—bent down). 
Synonyms.—Hook worm. Dochmius Cernua. 
Distribution. — Frequently found in Southern 
United States. 
Description.—A thread-like worm, yellowish white 
in color; the body is rigid and attenuated at both 
ends; the mouth is circular and provided with four 
hook-like teeth; the buccal cavity is ovoid in shape; 
the male is one-half to three-fourths of an inch long, 
the female one inch. 
Life History. — The ova, reaching water or moist 
earth, hatch into the embryonic state; if conditions 
are favorable they moult in three days; in five days 
they moult the second time; when taken into the 
intestinal tract at this time they invade the mucous 
membrane (if not taken in at this stage they will 
perish in about four weeks) ; they now fasten them- 
selves to the mucous membrane and develop into 
the mature worm in about fifteen days; during this 
time they moult twice. 
Animals Infested.—The sheep and goat. 
Parts Infested. —Small and frequently the large 
intestines. 
Mode of Infestation. — Like other worms of the 
family Strongylidae, the pools of water, ponds, 
pastures and other food become contaminated by 
feces from infested sheep, laden with the ova; here 
