74 PROCEEDINGS OF THE NATIONAL MUSEUM. yol. 46. 



distinct or indistinct. Male usually with two spicules and female usu- 

 ally with two ovaries. Oviparous, viviparous, or ovo viviparous. 



Type family. — Strongylidae Cobbold, 1864. 



Weinland proposed the Strongyloidea as a family, but the name is 

 ill the form now used for the superfamily and it is erected as a super- 

 family in this paper. 



FamHy STRONGYLIDAE Cobbold, 1864. 



Family diagnosis. — Strongyloidea: Meromyarian. Caudal bursa 

 well developed and with each lateral lobe supported by six rays. 

 Buccal capsule present or absent; when present, slightly or well 

 developed. Oviparous; eggs segmenting when laid. Embryo usually 

 rhabditiform. In digestive, rarely in resphatory system. 



Type genus. — Strongylus MueUer, 1780. 



Subfamily STRONGYLIN^E: Railliet, 1893. 



Subfamily diagnosis. — Strongylidse : Buccal capsule well developed. 

 Parasites of the digestive, rarely of the respiratory tract. 

 Type genus. — Strongylus Mueller, 1780. 



Subfamily TRIOHO STRONG- YLIN^aE Leiper, 1908. 



Subfamily diagnosis. — Strongylidse : Buccal capsule lacking or only 

 slightly developed. Parasites of the digestive tract. 

 Type genus. — Trichostrongylus Looss, 1905. 



Family METASTRONGYLIDiE Railliet and Henry, 1910. 



Family diagnosis. — Strongyloidea: Polymyarian. Buccal capsule 

 present or lacking. Caudal bursa present or absent; when present, 

 frequently atypical in structure and number of rays. Oviparous, 

 with eggs in variable stages when laid, ovoviviparous or viviparous. 

 Embryo not rhabditiform (not known for Rictulariinse). In respira- 

 tory and circulatory systems, rarely m digestive. 



Type genus. — Metastrongylus Molin, 1861. 



Subfamily MIETASTRON-G^YrilN^ffi Leiper. 1908. 



Subfamily diagnosis. — Metastrongylidge : Bursa well developed and 

 conforming m general to the strongyle type. Eggs m varying stages 

 of development when laid. In respiratory and circulatory systems. 



Type genus. — Metastrongylus Molm, 1861. 



Subfamily PSKTTDALIIN-..^ JBailliet and Henry, 1909. 



Pseudalinae Railliet and Henry, 1910. 



Subfamily diagnosis. — Metastrongylida?: Bursa much reduced or 

 lacking; when present, with few and atypical rays. Mouth with or 

 without buccal capsule. Viviparous. Parasites of the respiratory 

 and circulatory apparatus. 



Type genus. — Pseuddlius Dujardin, 1845. 



