TRICHINELLIN^: 421 



Trichuris trichiura is found not only in man, but also in various 

 monkeys (T. palceformis, Rud.), as well as in lemurs (T. lemur is, Rud.). 



Other species are T. crenata in pig ; T. ovis in cattle, sheep, goat, and 

 pig (?) ; T. depressiuscula in dog ; T. campanula in cat ; T. uuguiculata 

 in rabbit and hare ; T. camdi in camel ; T. discolor in humped cattle ; 

 T. nodosus in mouse; T. alcocki in the thamin (India) ; T. globtilosa in 

 camel ; T. giraffce in giraffe. 



Sub-family. Trichinellinae, Ransom, 1911. 



Male without spicule ; females ovoviviparous. Larvae penetrate 

 muscles of host and become encysted. Genus : Trichinella. 



Genus. Trichinella, Railliet, 1895. 



Syn. : Trichina, Owen, 1835 ( nec Meigen, 1830). 



Very small Trichinelliruz, the males of which have two conical appendages at the 

 caudal extremity ; the vulva is situated at the border of the anterior fifth of the 

 body. There is only one species. 



Trichinella spiralis, Owen, 1835. 



Syn. : Trichina spiralis, Owen, 1835. 



The male measures 1*4 to i'6 mm. in length and 0*04 mm. in 

 diameter. The anterior part of the body is narrowed, the orifice of 

 the cloaca is terminal and lies between the two caudal appendages ; 

 internal to these are two pairs of papillae, dorsal one behind the other. 

 .The cloaca is evertible for copulation. The females measure 3 to 

 .4 mm. in length and 0*06 mm. in diameter ; anus terminal. 



Trichinella spiralis in its adult stage inhabits the small intestine 

 of man, pig, wild boar, rat. The young do not leave the body of the 

 host but become encysted in the muscles. Experimentally it develops 

 in the black rat (Mus rattus), the sewer rat (M. decuman us), the 

 domestic pig (Sus scrofa dom.), the wild boar (Sus scrofa ferox), the 

 domestic dog (Canis familiaris) , the fox (C. vulpes) the badger (Meles 

 taxus], the polecat (Putorhts fcetidus), the marten (Mustela faina), the 

 raccoon (Procyon lotor), the hippopotamus and the cat, and many 

 other mammals (rodents and carnivora) ; Trichinellae have been arti- 

 ficially introduced, by administering the encysted stage, into the dog, 

 the mole (Talpa europcea), the mouse (Mus musculus), the hare (Lepus 

 timidus], the rabbit (L. cuniculus), the hedgehog (Erinaceus europceus), 

 the marmot (Cricetus vulgaris), the vole, the dormouse, the sheep, the 

 calf, the horse, etc. Human beings and the pig, rat, mouse, guinea- 

 pig and rabbit are most easily infected ; less easily the sheep, calf and 

 horse ; with difficulty the cat, dog and badger. Trichinella can also 

 be reared in birds (fowl, pigeon and duck), but the young do not 



