NEMATODE PARASITES OF BIRDS 



15 



curved. Bursa (fig. 9) with a large lateral lobe and a small dorsal 

 lobe. The dorsal, lateral, and ventral ray systems originate in 3 

 stems, one to each system. Ventro-ventral ray slender and curved 

 ventrally, diverging from latero-ventral; the latter thicker and 

 closer to laterals. Postero-lateral ray thin and bent dorsally ; medio- 

 latcral and externo-lateral rays thicker and bent ventrally. Main 

 stem of dorsal ray branches, each main branch in turn bifurcating 

 near its base to form secondary branches, and the internal secondary 

 branches bifurcating near their tips; externo-dorsal ray short, ex- 

 tending only halfway to bursa margin. Prebursal papillae, slender, 



Figs. 8-10. — 8. Ornithostrongylus fabiai. Male bursa. After Travassos, 1021. 9, 

 Ornithostrongylus douglasi. Male bursa. 10, Same. Tail of female. Nos. 9-10 

 after theiler and robertson, 1915 



easily overlooked. Spicules 140 to 158/a long, dark brown, the proxi- 

 mal ends knob-like, the body longitudinally grooved and with a 

 convexly curved ridge on one side of the groove, and the distal end 

 terminating in a spine, a second spine originating in the posterior 

 third of the spicule. The telamon is lancet-shaped in outline, but 

 curved about the cloaca, with a short blunt spine directed backwards, 

 and is light brown. 



Female length averages 5.G3 mm. ; width about 105 to 109/x. Body 



terminates in a blunt point 80/x long, its tip slightly curved (fig. 10). 



Vulva a transverse or oblique slit about 800/x from the tip of the tail. 



A short vagina leads to the muscular ovejector, which is about 



3(512—27 3 



