OXYURID.E 



Lagocheilascaris minor, Leiper, 1909. 



Male, 9 mm., tail sharply curved. Spicules colourless, 3*5 and 

 4 mm. long. More than twenty-four pairs of pre-anal papillae, at least 

 five pairs of post-anal. Female, 15 mm. Straight posteriorly. Vulva 

 6 mm. from head with two lips. Eggs, 65 /JL in diameter. Host : 

 man, cutaneous abscesses. Trinidad. 



Family. Oxyuridae. 

 Genus. Oxyuris, Rudolphi, 1803. 



Mouth unarmed. The three labial papillae are only slightly protuberant, the 

 oesophagus is long and presents two well-marked bulbs. The vulva is in the anterior 

 part of the body. 



Oxyuris vermicularis, Linnaeus, 1767. 

 Syn. : As carts vermicularis , L. ; Fusaria, Zeder, 1803. 



Colour white, the striated cuticle forms projections at the anterior 

 end which extend some distance back along the middle of the ventral 

 and dorsal surfaces ; the longitudinal lateral flanges of the skin corre- 

 sponding to the lateral lines are well seen in transverse sections ; there 

 are three small retractile labial papillae around the mouth. The 

 male measures 3 to 5 mm. in length, and shortens on death; the 

 posterior extremity of the body is curved ventrally and presents six 

 papillae. Spicule JO/JL long, hook-like. The female is lomm. in length 

 and 0*6 mm. in diameter ; the anus is about 2 mm. in front of the tip of 

 the tail ; the vulva is in the anterior third of the body ; the eggs are 

 oval, asymmetrical, with double-contoured shells, and measure 50 //, to 

 55 //, by 16 fji to 25/4; they are deposited with clear, non-granular 

 tadpole-like embryos already developed. 



Habitat. Adults in large intestine of man. Young forms in small 

 intestine and often in the appendix. 



The worm lives in the lower part of the small intestine, caecum and vermiform 

 appendix, and before becoming adult undergoes two or three moults (Heller). 

 According to Wagener the worms at times live in the gut wall, giving rise to calcareous 

 nodules. When the uterus of the fertilized females begins to fill with eggs they leave 

 the caecum and travel through the colon to the rectum. The uterus is now packed 

 with eggs which contain a tadpole-shaped embryo. Egg-laying now takes place, 

 partly in the rectum, partly outside, the mode of exit being not only passive through 

 defaecation but also an active one on the part of the worms when the patient is in bed. 

 In this case the worms crawl out of the anus, producing a most intolerable itching as 

 they scatter their eggs between the nates and the perinaeum. From here in the case 

 of girls they may get occasionally into the vulva and vagina, and even into the 

 oviducts and so into the body cavity. The worms also may wander through the 

 alimentary canal in the opposite direction, getting out occasionally through the 

 mouth. Recently a role has been assigned to them, as to other gut parasites, in 

 appendicitis and typhlitis. 



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