31 



Family ASCARIDAE 



Ascaris lumbricoides — Intestinal parasite of man and of hog. 

 That of the hog has been regarded by some writers as a distinct 

 species, Ascaris suilla. 



Form and structure— Body milky-white, long (males 15-17 em.; 

 females 20-25 cm.) ; elastic and pointed at the extremities. Resem- 

 bles a large earthworm. Head with three lips, — a dorsal and two 

 ventro-lateral, — bearing papillae. Male has caudal end curved 

 towards the ventral side and bearing two spicules. Female with 

 caudal end conical and straight; vulva about the anterior third of 

 the body. 



Development — The ellipsoidal egg 60-75/^ long covered by a 

 transparent mammillated sheath which gives it a very characteristic 

 appearance. Scattered with feces, are capable of direct develop- 

 ment, without any intermediate host, when ingested by man or hogs. 



Heterakis vesicularis — A roundworm of chickens. Lives in 

 caecum and sometimes present in such numbers as to cause death 

 by mere mechanical obstruction. Males 7-13 mm. long, spicules 

 unequal; female 10-15 mm. long. Adults and eggs pass out with 

 droppings of the fowls and, developing in presence 6f moisture, 

 without intermediate host, give rise to adults when swallowed by 

 chickens. Best controlled by cleanliness in yards, shifting to un- 

 contaminated soil, soil sterilization or even by deep ploughing or 

 spading. 



Family STRONGYLIDAE 



Bunostomum phlebatomum — {Monodontus phlebaioinus) . A 

 "hookworm" of cattle, occurring in the small intestine. See, Conradi 

 and Barnett, Bull. 137, South Carolina Exper. Sta. Male 10-12. mm, 

 female 16-19 mm. Mouth cavity enlarged to form a buccal capsule, 

 with strong dorsal tooth projecting forward into its cavity and with 

 two ventral buccal teeth and two subventral buccal teeth or lancets. 



Necator amepcanus — (Uncinaria americana, Ankylostoma ameri- 

 cana). The American hookworm. The cause of uncinariasis, one 

 of the most important and most common diseases of the South, 

 Porto Rico, Cuba and other parts of tropical America. Charac- 

 terized by great anemia, weakness, colicky pains, perverted appetite, 

 such as "dirt eating", inertia. Victims often underdeveloped 



