26 BULLETIN 140, UNITED STATES NATIONAL MUSEUM 



AMIDOSTOMUM MONODON (Linstow, 1882) Skrjabin, 1915 



Synonyms. — Strongylus monodon Linstow, 1882 ; Sclerostomy 

 monodon (Linstow, 1882) Stossich, 1889. 



Host. — Oldemia nigra. 



Location. — Gizzard. 



Morphology. — Amidostomum (p. 19) : Mouth cavity (fig. 23) 

 armed with a large triangular tooth. Wall of cavity without sup- 

 porting ribs. 



Male unknown. 



Female 16.5 mm. long by 14G> wide, the ratio of width to length 

 being 1 : 116. Esophagus 1/23, tail 1/55 of total body length, the 

 tail conical and rounded. Vulva at posterior fifth of body, dividing 

 body length in ratio of 17 : 4. Eggs 92/* long by 62/x wide. 



Life history. — Unknown; probably simple and direct. 



Distribution. — Europe. 



Genus EPOMIDIOSTOMUM Skrjabin, 1916 



Generic diagnosis. — Amidostominae (p. 18) : Meromyarian. Body 

 filiform, the anterior extremity attenuate. Cuticle thick and trans- 

 versely striated. Postcervical papillae present, but not prominent. 

 Head distinct, bearing on its dorsal and ventral surface a pair of 

 nodules (also referred to as lips or papillae) which are directed 

 posteriorly and are either uncinate or obtuse at their free extremity. 

 According to Seurat the head bears a pair of lateral papillae on each 

 side. Cephalic cuticle ornamented with a pair of epaulets or fes- 

 toons, which, according to Skrjabin, have zig-zag incisions in their 

 posterior portion. Buccal capsule lacking, according to Skrjabin, or 

 short and reduced, according to Seurat. Esophagus with 3 chitinous 

 axial lamellae. Male with uncinate tail, concave ventrally, with a 

 bursa which, according to Skrjabin, is delicate or, according to 

 Seurat, has thick lateral lobes marked with a strong reticulate stria- 

 tion and folded over each other ventrally. The ventro-ventral and 

 latero-ventral rays are in relation with each other as opposed to the 

 other bursal rays ; Seurat says they are parallel, but Skrjabin says they 

 are separated and figures them as slightly divergent. According to 

 Seurat, the postero-lateral and medio-lateral rays are slender, contig- 

 uous, and elongate, and the externo-lateral ray is short ; according to 

 Skrjabin, the externo-lateral ray is related to the 2 other lateral rays, 

 which are so united as to leave only a slight cleft between them ; Skrja- 

 bin's figure indicates that the lateral rays have a common stem which 

 divides to form the externo-lateral ray and the common stem of the 

 2 other laterals, and that this latter common stem divides a half to 

 two-thirds of its length from its base to form these 2 rays. The 



