NEMATODE PARASITES OF BIRDS 19 



buccal capsule and from E ' pomidiostomum in having no posteriorly 

 directed epaulets. 



Genus AMIDOSTOMUM Raillet and Heary, 1909 



Generic diagnosis. — Amidostominae (p. 18) : Worms of general 

 trichostrongyle conformation and affinities, but with a buccal cap- 

 sule provided with 1 or 3 pointed teeth at its base; the buccal cap- 

 sule is comparatively wide and thick-walled. The esophagus has 3 

 chitinous axial lamellae along its entire length or except for a 

 terminal unarmed region, the bulb. Tail of female elongated and 

 digitiform, with lateral caudal pores about the middle of its length. 

 Tail of male with bursa having 2 large lateral lobes; a median lobe 

 distinctly or indistinctly defined. Dorsal ray bifurcates to form 

 2 branches, each of which ends in a bifurcation with the tips approxi- 

 mately on the border of the dorsal lobe. Externo-dorsal ray origi- 

 nates in some cases (A. chevreuxi) at the base of the dorsal ray in 

 a common stem, but in other cases (A. raillieti) it originates in a 

 mass from which all the rays except the dorsal take origin. There 

 is a shortening of the externo-dorsal and the externo-lateral evi- 

 denced by a failure to closely approach the bursal margin in any 

 case and to be greatly reduced in extreme cases, which may be re- 

 garded as a feature of distinctive generic value. The medio-lateral 

 and postero-lateral rays are contiguous proximally, but divergent 

 distally. The ventro-ventral and latero-ventral rays are widely di- 

 vergent, the latter more closely associated with the shortened ex- 

 terno-lateral ray than with the ventro-ventral. A pair of volumi- 

 nous almost contiguous papillae occur on the posterior lip of the 

 cloaca. Prebursal papillae present. Spicules equal, each divided 

 into 2 separated prolongations posteriorly along most of their length. 

 A straight gorgeret or telamon present. Vulva a transverse slit, 

 posterior to the middle of the body. Ovejectors divergent and op- 

 posed; uteri opposed; ovaries parallel, very long, extending towards 

 the anterior end of body. 



Type species. — Amidostomum anseris (Zeder, 1800) Railliet and 

 Henry, 1909. 



At the time this genus was proposed by Railliet and Henry, they 

 designated A. anseris (Zeder) as type. Subsequently Seurat has 

 designated Strongylvs nodulosus Rudolphi as type, stating that Zeder 

 confused worms belonging in 2 genera {Amidostomum and Epomi- 

 diostomuni) in his Strongylus anseris. Under the zoological code, 

 Amidostomum is fixed by its type and must stand or fall with it; a 

 new type can not be designated for the reason given by Seurat. The 

 proper procedure appears to be to restrict S. anseris to one of 

 Zeder's species. 



