NEMATODE PARASITES OF BIRDS 



327 



850//. to 1 mm. in 4 months, at which time sexual differences appear. 

 The smallest worm they have seen in the eye was 4 mm. long and 

 they have found mature worms in chickens 10 days old. They con- 

 clude that infection takes place by mature worms entering the eye 

 in soil as chickens dust themselves. Since worms of the genus Oxy- 



yooy^. 



OV. 



vg- 



int. 



x. 



ret. 



390. 



Figs. 390-391. — Oxyspiruba mansoni. 890, Postkbiob end ov female, {int., Intestine; 

 ov., OVARY; ret., recti- m ; iff., vagina; nil., vulva; x., cells SUBBOUNDZNG rectum.) 

 391, Posterior end of male, a, Lateral view. (dct. ej., Ejaculatory duct; int., 

 intestine; sp., SPICULES; v.s., seminal vesicle.) b. Ventral view. After Ransom. 

 1904 



spirura probably have life histories comparable to those known for 

 spirurids and filarids in general, this theory does not seem tenable 

 and it is probable that an intermediate liost is necessary for their 

 development. Such hosts would probably be insects, crustaceans, 

 or similar small animals commonly eaten by chickens and related 

 birds. 



Distribution. — North America (United States (Florida)), South 

 America (Brazil), Asia (China (Annam)), Africa (Belgian Congo); 



