NEMATODE PARASITES OF BIRDS 



23 



Morphology. — Amidostomum (p. 19) : Body slender, faintly red 

 with transverse striations. No lateral alae; postcervical papillae 

 very small, subsymmetrical ; excretory pore ventral, between nerve 

 ring and postcervical papillae. Buccal cavity (lig. 20) 7 to 8fi 

 deep and 10/i. wide, with very thick walls, and with a large tri- 

 angular dorsal tooth having a wide base and a sharp tip which turns 

 dorsad. There are 4 small sessile cephalic papillae. No pharynx. 

 The cylindrical esophagus is armed with 3 axial triturating lamellae 

 and is in relation posteriorly with an unarmed bulb of the same 

 width, not differentiated externally, which is without masticatory ap- 

 paratus. Nerve ring at middle of esophagus. 



•Male 7.25 to 8 mm. long by 80^ wide, and terminating in an un- 

 cinate tail concave ventrally. Esophagus and bulb 63C/x long. 



Figs. 20-23. — 20, Amidostomum chevkicuxi. Anteiuor end. a, Dorsal view ; b, 



LATERAL VIEW. 21, SAME. MALE BURSA. 22, SAME. OUTLINE OF BURSA; LATERAL 



view. Nos. 20-22 after Seurat, 1918. 23, Amidostomum monodon. Anterior 

 end. Aftf.b Linstow, 1882 



Bursa (figs. 21 and 22) with 2 large lateral lobes, 105/* long, with 

 their free borders folded towards the ventral surface, and with a dor- 

 sal lobe which is not distinctly delimited. The externo-dorsal ray 

 originates from the dorsal stem, but its relations otherwise are with 

 the lateral lobes and the rays other than the dorsal ; it is short, as is 

 the externo-lateral ray; all other rays extend to the bursa margin ex- 

 cept the latero-ventral which extends almost to the bursa margin. 

 A pair of large sessile papillae, contiguous or almost so, on the poste- 

 rior margin of the cloacal aperture. Prebursal papillae subsymmet- 

 rical and briefly pedunculated. Spicules 120^ long, each cleft dis- 

 tally for half its length into 2 unequal branches. Telamon (gor- 

 geret) straight, falciform, G0/x long. 



Female 12.8 mm. long by 120/x wide, terminating in an elon- 

 gate digitiform tail 265/u. long. Nerve ring 3/7 of esophagus 

 length from head. Esophagus and bulb 840/x long. Vulva a trans- 

 verse slit, 90/x long, slightly salient, in the posterior fourth of the 

 3613—27 4 



