6 PR0CEEDIN08 OF THE NATIONAL MUSEUM. vol. r,0. 



unpaired ray ; and with a buccal capsule present or absent in both sexes, 

 or if the male is not provided with a well-developed bursa, the buccal 

 capsule is usually present in both sexes; eggs usually (except one group) 

 with thin shells Strongjdoidea, p. 106. 



A buccal capsule never present (except in some fish parasites of the sui^er- 

 family Filarioidea) and bursa never developed to the extent or in the 



form of the typical bursa of strongyles 4. 



4. Usually comparatively thick in relation to length. Mouth usually with three 

 lips, but may be witliout lips. Oviparous Ascaroidea, p. 39. 



Usually very long, slender forms. Mouth with 2 lips or surrounded with 

 papilhie. Oviparous, ovoviviparous, or viviparous Filarioidea, p. 178. 



ANGIOSTOMOIDEA Hall, 1916, new superfamily. 



Superfamily diagnosis. — Nematoda (p. 4) : Two heterogenetic 

 generations, one of free-living rliabditiform males and females and 

 one of parasitic hermaphroditic, syngonic, or parthenogenetic filari- 

 form females. 



Type-fcnnili/.—AiigiostoimdiXG Brann, 1895. 



Family ANGIOSTOMIDAE Braim, 1895. 



SynonyTYi. — Rhabdiasidae Railliet, 1915. 



FamMy diagnosis. — Angiostomoidea (p. 6) : With the characteris- 

 tics of the superfamily. 



Type-genus. — Angiostoma Dujardin, 1845. 



Since this paper was written, Railliet (1915) has published a paper 

 in which he places Strongyloides in the family l\hal)diasidae. This 

 family is proposed by him casually and without comment, diagnosis, 

 or indication that it is new, and the present writer is unable to state 

 the grounds for this action. Previously Eailliet (1893) had listed 

 Strongyloides in the family Angiostomidae as given here. 



Genus STRONGYLOIDES Grassi, 18796. 



Synonyms. — Strongiloides Grassi, 18T9a/ Pscudo-rliabditis Per- 

 roncito, 1881. 



Generic diagnosis. — Angiostomidae (p. G) : Parasitic form Avith 

 mouth opening directly into the relatively very long subcylindrical 

 esophagus. Mouth surrounded by small papillae, apparently six in 

 number, according to Ransom (1911(z) and surrounded by four lips, 

 according to Gedoelst (1911). Cuticle fineh^ striated transversely, 

 sometimes presenting also the appearance of longitudinal striation. 

 Vulva posterior of the middle of the body. Uterus double. Two 

 ovaries. Eggs ellipsoidal, with thin shells. Free-living form with 

 mouth opening into a vestibule or pharynx, followed by an esopha- 

 gus of which the anterior portion is fusiform and the posterior por- 

 tion is globular. The posterior bulb of the esophagus in the free- 

 living form is furnished with a toothed masticatory apparatus. 

 Free-living male with two short equal spicules. 



