PARASITOLOGY. 15 i 



TRICHOTRACHELIDAE. 



The family Trichotrachelidae includes a group of 

 blood sucking: worms, provided with a nude head; 

 in the adult state they infest the intestinal tract. 



(Trix— a hair) 

 Trichocephalus Depressiusculus fCephale— head) 



(Depressus depress) 

 Syno7iym. — Whip worm. 



Distribution. — Found occasionally in the United 

 States, also in Europe. 



Description. — This worm in shape resembles the 

 old fashioned *' black snake" whip; the posterior 

 part of the body is about the calibre of a thread; the 

 anterior two-thirds is attenuated, resembling a hair; 

 it is white in color; its mouth is nude; the large part 

 of the body of the male forms a coil ; the correspond- 

 ing part of the female is straight or slightly curved ; 

 the male is provided with a spicula; the vulva of the 

 female is located in the anterior 

 portion of the large part of the 

 body ; the male measures from 

 one to one and one-fourth inches 

 in length; the female from one and 

 one-fourth to one and one-half 

 Fig. 59— inches. 



'sit°c"u3."" °''"" i^ile History.-the ova, placed 



1, Female. in water and kept at a warm tem- 



iceth'aiic extremity, perature will hatch and develop 



b, Caudal " complete embryos in from four to 



five months ; if these be fed to 



dogs they develop to the adult stage; drying or 



desiccation of the eggs or embryos stops their de- 



