106 THE ORICrN OF 



worms is not yet well understood, since their or- 

 gans of generation have not yet been discovered. 



It cannot therefore be ascertained at present, 

 whether the hermit vesicular worm belongs exclu- 

 sively to man, or whether the social vesicular worm 

 pertains exclusively to other animals.(S7 ) 



^ LXIV. The tricocephalus which Bloch{2S) 

 says he has found only in the human coecum, has 

 been discovered by Goeze,[2Q) in the intestines of 

 the male mouse ; by Wagler in the horse,(30) and 

 by Ruusch in the wild boar.(31) Another trico- 

 cephalus, having fangs at the head in form of 

 a crown, has been found by Pallas^ in the Lacer- 

 ta apoda, as we have already said elsewhere. (3S) 

 § LXV. In passing from the tricocephalus to 

 the ascaris vermiciilaris, we must recollect that 

 this worm is found in the intestines of the Rana, 

 temporaria. 



Its resemblance to the human ascaris is such 

 that Goeze pretends that our worms are innate in 

 us. 



He could not perceive the least difference be- 

 tween them, and, as an exact and impartial obser- 

 ver, was obliged, perhaps against his opinion, to 

 reduce them to the same species, and to give a de- 

 scription of them together.(33) 



This excellent and illustrious naturalist saw, 

 on another occasion, the ascaris vermicularis, in 

 tne. intestines of the pike and of the aquatic sala- 

 mander.(34) All the ascarides vermiculares are 

 viviparous like tlic liuman. 



