NEMATODE PARASITES OF BIRDS 



291 



alae (fig. 354c). The caudal alae have 6 pairs of ray-like papillae, 

 of which 4 are preanal and 2 postanal. In a worm 9.3 mm. long, 

 the 2 slender, equal spicules measure 6 mm. long by 10>n wide. The 

 cloacal aperture in a worm this size is 110/x from the posterior 

 extremity. 



Female 7 to 14 mm. long by 200 to 400/i. wide. Tail straight and 

 obtusely conical, with the anus not far from tip. Vulva in anterior 

 part of body; it is a longitudinal cleft with 2 prominent lips. 



Life history. — Unknown. 



Distribution. — Europe and Asia (Russian Turkestan). 



HISTIOCEPHALUS TRIDENS Gendre, 1921b 



Host. — Primary : Traehelotis senegalensis; secondary : Unknown. 

 Location. — Under lining of gizzard. 



Morphology. — Histiocephalus (p. 290) : Red or reddish-yellow 

 worms when alive, brown after killing so that internal anatomy is 



3fl? 



Figs. 354-355. — Histiocephalus laticaudatus. 354, a. Front view and b, lateral 

 VIEW of head; c, male tail. After Drasche, 1S84. 355, Male. After 

 Skrjabi.nv, 1016 



difficult to study. Body filiform; cuticle transversely striated. 

 Head (fig. 356 a and b) distinctly set off from body by a furrow, 

 following which is a cuticular collar, 16/* high in the male, 2<V in the 

 female, formed by narrow projecting ridges. Mouth with 4 lips, the 

 2 laterals being much larger than the dorsal and ventral. The 

 former (i. e., the laterals) are trilobed, the lateral lobes of each 

 bearing a small papilla ; on the inner surface each lateral lip has 4 

 triangular teeth and on the outer surface 2 membranous fan-shaped 

 expansions, each divided into 3 divergent, posteriorly directed 

 branches ending in conical points. The dorsal and ventral lips are 

 smaller and less distinct than the laterals, reaching only about half 

 the height of the latter; each has 2 large projecting papillae at its 

 base. 



Male 5.2 mm. long by 20G> wide. Cloacal aperture 96^ from pos- 

 terior extremity (1/54 of total length). Caudal alae (fig. 356 c) large 



