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CHAPTER XIV. 



Ascaridce. The mouth is surrounded by three promi- 

 nent lips, one dorsal and two ventral. The cloaca in 

 the male is subterminal, there is no copulatory bursa, 

 there are two equal spicules, and numerous pre-anal and 

 post-anal papillae. 



In the female there are two ovaries, and the genital 

 opening is anterior to the middle of the body. The 

 Ascaridae include a large number of species parasitic 

 in birds, mammals and reptiles. The important species 

 in man is the Ascaris lumbricoides. 



Ascaris lumbricoides ("Round-worm") is found in the 

 small intestine, but may wander into the stomach and be 

 vomited, or pass into the large intestine and be expelled 

 with the motions. The male is 15 to 25 cm. by 3 mm. 

 in breadth. The tail is strongly curved ventrally. There 

 are two spicules, seventy to seventy-five papillae ; seven 

 of these are post-anal. 



The female is 20 to 40 cm. by 5 mm. in breadth. The 

 tail is straight and the anus is close to it. The uterine 

 tubes are much convoluted and are ten to fifteen times 

 the length of the worm. The opening of the vagina is 

 at the junction of the anterior third of the body and the 

 middle third. 



The three prominent lips characteristic of the genus 

 are well marked. The dorsal lip carries two sensory 

 papillae, the two ventral lips each have one. 



The common round-worm of man is the Ascaris 

 lumbricoides, which occurs in all countries, but in 

 the temperate regions is most commonly found in 



