RHABDITINAE 41 



7. Macrolaimus Maupas, 1900, nee Ditlevsen, 1919. 



Cuticle very finely striated. Head without lips. Mouth 

 widely open, bordered by six short, stout bristles. Buccal 

 cavity wide, cup-shaped, its wall in two portions, the anterior 

 thin and transparent, the posterior thick and dark-coloured. 

 Oesophagus with thick anterior portion, separated by a long, 

 narrow neck from a well-developed posterior bulb. Partheno- 

 genetic. Female genital tube single, anterior, with long 

 reflexion. Oviparous. Excretory system consists of lateral 

 canals. 



Hab. Soil. 



Genotype : M. crucis Maupas, 1900. 



Maupas, 1900, Arch. Zool. exp. et gen., Paris, (3) viii, 578. 



8. Diplogaster M. Schultze, in Carus, 1857. 



Syn. Diplogasteroides de Man, 1912 ; Rhabditolaimus Fuchs, 

 1916 ; Fuchsia Micoletzky, 1922. 



Cuticle with transverse and also longitudinal striations. 

 Head not distinct, sometimes with lips, sometimes with one or 

 two crowns of small bristle-like papillae. A fold of cuticle, 

 which may be longitudinally ribbed, sometimes present 

 immediately behind the mouth. Lateral organs variable, 

 probably always present, occasionally showing sexual differ- 

 ences. Buccal capsule wide and often deep, but variable in 

 shape, thick-walled, with one large (dorsal) or two or three 

 small, movable teeth at its base, or without teeth. Oesophagus 

 with a muscular anterior bulb and a non-muscidar posterior 

 bulb-like swelling. Caudal end of male with or without alae, 

 and with nine or ten pairs of papillae. In forms without 

 alae the papillae are usually bristle-like. Two spicules and 

 an accessory piece, of very variable shape, present. Testis 

 usually single. Female genital tubes usually paired, opposed, 

 reflexed. Usually oviparous, sometimes viviparous. Some 

 species hermaphrodite, according to Cobb. Caudal glands 

 absent. 



Hab. Fresh water, soil, decaying matter. Some species 

 have been found on plants, others in dead insects. It is 

 uncertain whether any are true parasities. 



Genotjrpe : D. micans M. Schultze, in Carus, 1857. 



Max Schultze, in Carus, 1857, Icon. Zootom., Erste Halfte, 

 PI. VIII, fig. 1 ; de Man, 1884, Diefrei . . . lebenden Nem. der 

 Niederl. Fauna, 84; Fuchs, 1915, Zool. Jahrb., Syst., xxxviii, 

 158; Cobb, 1918, in Ward and Whipple, Freshwater Biology, 

 488; Micoletzky, 1922, Arch. f. Naturg., Abt. A, Ixxxvii, 402. 



Micoletzky (1922) divides this genus into two subgenera, 

 Diplogaster and Fuchsia. The latter appears to be identical 



