ANIMAL PARASITES. 



117 



drinkingwater containing small aquatic crustaceans 

 {Cyclops quadricornis) which themselves harbor the 

 embryos. The embryos 

 penetrate the intestinal 

 wall, reach the subcu- 

 taneous tissues, and 

 there attain full develop- 

 ment. The seat of elec- 

 tion is the lower ex- 

 tremities, particularly 

 about the heels, yet the 

 parasite has been found 

 in other parts of the 

 body. It is said that 

 the worm can be felt 

 beneath the skin "like 

 a bundle of strings." 

 When the worm is ma- 

 ture it breaks through 

 the integument, forming 

 at first a little vesicle, 

 later a small discharg- 

 ing ulcer, and from the 



r 1 1 1 I^IG- ^- — F'ilaria medinensis; a, anterior 



bottom of the latter the extremity; O, mouth; P, papillae; h, fe- 



\^r.r.A r.^^^rs4-\^^r.r. ^-^^ malc, reducccl to less than half normal 



head sometimes pro- ^^ult size; c, larv^, enlarged. (Braun, 



trudes. Embryos are after ciaus.) 

 discharged through the opening in the skin, more par- 

 ticularly when water is applied. After getting rid of 



