136 TROPICAL MEDICINE AND HYGIENE 



TRICHINELLA. 



Trichinella. The thin and thick portions of the worm 

 merge gradually into each other. There is not the abrupt 

 transition as in the Trichocephali. The females are vivi- 



FiG. 62. Trichinella spiralis. a, mature female, "intestinal trichina"; 

 E, embryos; V, vulva; Ov, ovary; 6, mature male, 'f intestinal trichina"; 

 T, testes ; c t newly - born larva ; d> larva of trichinella in the muscles ; 

 e, encapsulated trichinella of the muscles. (After Claus.) 



parous and in their whole existence the worms are 

 parasitic. Two mammalian hosts, not necessarily of 

 different species, are required for the development. 



Females measure 3 to 4 mm. in length and 0-05 mm. in 



