RHABDITOID PARASITES. 9/ 



mencement, the young have the characteristics of the genus Rhabditis, 

 but lose them while yet in the maternal body; after they have 

 attained a certain size, they cease to eat, and undergo further de- 

 velopment only after having found an opportunity of becoming trans- 

 ferred into the lung of a frog, and thus exchanging their former mode 

 of life for a parasitic one. 



The adaptation to the circumstances of parasitic life is much more 

 complete in these worms than is the case in Rhabditis appendicu- 



FIG. 61. Rhabditoid form of Khdbdoncma (Ascaris) niyro- 

 venosum. A . Male ; B. Female, with embryos in 

 various stages of development. 



FIG. 62. Mature em- 

 bryo of Rhabdonema 

 niyrorenosum. 



lata. When they reach the lungs of their host, the young parasites 

 grow to a length of almost an inch, and possess scarcely the slightest 



G 



