134 



TROPICAL MEDICINE AND HYGIENE 



The female is 50 mm. in length and the male about 

 45 mm. They are found in the caecum, and occasionally, 

 when numerous, in the ascending and transverse colon 

 rarely in the vermiform appendix. 



Three-fifths of each worm are formed by the thread- 

 like anterior extremity. The mouth is unarmed, and the 

 anterior two-fifths contain the long oesophagus which 



FIG. 61. Trichocephalus trichiurus. On the right, male; on the left, 

 female. Below, egg. 



appears to be moniliform. A considerable length of the 

 thin anterior end may be embedded in the intestinal 

 mucosa. In the female the genital opening is just at the 

 well-marked junction of the broad and thin parts of the 

 worm. The ovary is posterior. The caudal extremity of 

 the male is sharply curved on itself, and from the cloaca 

 may be extruded a rounded projection in the summit of 

 which is the opening of the vas deferens (fig. 61.) 



Trichocephalus trichiurus, is found in temperate climates 

 but is much more common in inhabitants of tropical 

 countries. Usually only a few worms are present in 

 each individual. 



