112 ASCAROIDEA 



which is funnel-shaped. The large tooth is very well de- 

 veloped, occupying almost the whole lumen of the pharynx. 

 It is asymmetrical (subventral), as in Oiicliolaimus . The 

 remaining two teeth are blunt tubercles. Oesophagus slightly 

 swollen behind. Caudal end of male with alae and three 

 pairs of fine sublateral bristles, one pair preanal and two 

 postanal. Both preanal and postanal papillae present. 

 Spicules long, imequal, the longer (right) slightly S-shaped, 

 the other only slightly curved and two-thirds of the length 

 of the right. Female genital tubes paired, opposed, reflexed. 

 " Tubiform organ " absent. Caudal glands and spinneret 

 present. 



Hab. Marine. 



Genotjrpe : O. calvadosicus de Man, 1890. 



de Man, 1890, Mem. Soc. Zool. France, iii, 189. 



4. Mononchulus Cobb, 1917. 



Cuticle unstriated and apparently without bristles. Head 

 not distinct, with six lips and six papillae, but without bristles. 

 Lateral organs very inconspicuous, semicircular. Pharynx 

 large, with three teeth, of which one of the subventral is con- 

 siderably the largest. Oesophagus comparatively long, some- 

 what swollen posteriorly. Apparently hermaphi'odite, the 

 anterior branch of the genital tube longer and reflexed, and 

 functioning as a female organ ; the posterior branch small, 

 outstretched, producing spermatozoa. Spinneret opens 

 ventraUy and subterminally. 



Hab. Fresh water. 



Genotype : M. ventralis Cobb, 1918. 



Cobb, 1917, Soil Science (May), 447, 453; 1918, Contr. Sci. 

 Nematol., vii, 195. 



5. Rhabdodemania nom. nov. 



Syn. Demania Southern, 1914, nee Laurie, 1906, 7iec Steiner, 

 1914. 



Cuticle smooth. Head with ten bristles in one or two 

 crowns. Lateral organs indistinct. Pharynx large and deep, 

 the hinder portion having three longitudinal chitinoid rods, 

 each with an anterior tooth. All the teeth are apparently 

 of equal size. Oesophagus slightly swollen posteriorly. 

 Caudal end of male without preanal papiUae or supplementary 

 organs. Spicules equal. An accessory piece present. Female 

 genital tubes paired, opposed, reflexed. Caudal glands 

 present. 



Hab. Marine. 



Genotype : D. major Southern, 1914 (by page precedence). 



Southern, 1914, Proc. E. Irish Acad., xxxi, 41. 



