148 



NEMATHELMINTHES 



the death of the host. The embryos normally bore their way 

 into the body of the fresh-water Ci/clojis, and are re-introduced 

 into their Vertebrate hosts with the drinking -water. It is 

 usually stated that the female alone is known, and that it is 

 uncertain whether it is hermaphrodite or whether both sexes are 

 present in the Cyclops. Recently Dr. Charles 1 has descril>ed a 

 specimen found in the mesentery of a human subject, from an 

 orifice in the middle of whose body he was able to draw a much 

 smaller specimen, and he thinks this may be the long-sought-for 

 male. 



Filaria immitis Leidy, the cruel worm, is common in dogs 



FIG. 73. A, View of the he-art of a .log infested with Filaria immitis- Leidy ; the right 

 ventricle and l>ase of the pulmonary artery have been opened, a, Aorta ; b, pulmonary 

 artery ; c, vena cava ; <l, right ventricle ; e, appendix of left auricle ; f, appendix of 

 right auricle. B, A female F. immitis removed from the heart to show its length. 

 Natural size. 



in China and the East generally. It is not unknown in America 

 and Europe. It occurs in such large clusters in the right ventricle 

 that it is difficult to see how the circulation can proceed. The 

 intermediate host is unknown, but from the prevalence of the 



1 .S'ci. Mem. Medic. Officers, Army of Iwlia, vol. vii. 1892, p. 51. 

 2 Shipley, Proc. Phil. Sue. Camb. vol. viii. 1892-95, p. 211. 



