RHABDITINAE 37 



Hab. Decaying material, damp soil or water (fresh or 

 marine). Some species parasitic, chiefly in insects. 

 Genotype : R. terricola Dujardin, 1845. 



Dujardin, 1845, Histoire naturelle des Helminthes, Paris, 239 ; 

 de Man, 1884, Die frei . ."'. lehenden JSematoden der Niederl. 

 Fauna, Leiden, 118; Micoletzky, 1922, Arch. f. Naturg., 

 Abt. A, Ixxxvii, 245. 



2. Rhabdias Stiles & Hassall, 1905. 



Syn. Angiostoma Dujardin, 1845, e. p. {Angiostoma and 

 Angiostomum auctt.) ; Ehabdonema Leuckart, 1879, et auctt., 

 e. p. 



Free-living generation. Microscopic forms. Sexes separate. 

 Body fairly stout. Mouth without lips. A short buccal 

 capsule present. Oesophagus with a fusiform prebulbar 

 swelling and a pyriform posterior bulb. Tail of male conical, 

 with a short terminal spike and narrow lateral alae. Four 

 pairs of preanal and three pairs of postanal papillae present, 

 all lateral in position. Spicules equal, short and stout. 

 Apparently no accessory piece. Tail of female conical. 

 Vulva somewhat behind middle of body. Uterine branches 

 opposed. Eggs very few and large. Embryos hatch within 

 the uterus, and are retained until the death of the female. 



Parasitic generation. Much larger than the free-living 

 generation, and consisting of " female " forms only (pro- 

 tandrous hermaphrodites). Slender forms, without lips. A 

 short, cup-shaped buccal capsule present. Oesophagus cylin- 

 drical, with a slight constriction about the middle, and without 

 a posterior bulb. Tail conical. Vulva near the middle of the 

 body, opening directly into the uterine branches, which are 

 opposed. Ovaries reflexed. Eggs segmenting when laid. 



Hab. Lungs of Amphibians and Reptiles. (Free-living stages 

 in faeces of these animals or in the soil). 



Genotype : R. [Ascaris] bufonis (Schrank, 1788). 



Schrank, 1788, Verzeichniss der . . . Eingeweideiviirmer, 

 Miinchen, 11; Dujardin, 1845, Histoire naturelle des Hel- 

 minthes, Paris, 262 {Angiostoma entomelas, not A. limacis) ; v. 

 Linstow, 1890, Arch. f. Naturg., i, 185; Stiles & Hassall, 1905, 

 U.S. Dept. Agric, Bur. Anim. Indust. Bull. 74, 123, 150; 

 Schleip, 1911, Arch. f. Zellforschg., Leipzig, vii, 87. 



3. Strongyloides Grassi, 1879. 



Syn. Rhabdonema Leuckart, 1879, et auctt., e. p.; Pseu- 

 dorhabditis Perroncito, 1880, nee Sziits, 1912; StercoraUs 

 Tanaka, 1910. 



Free-living generation. Microscopic forms, comparatively 

 stout. Sexeg separate. Mouth with four indistinct lips and 



