68 ASCAROIDEA 



Male of typical cylindrical shape. Body of mature female 

 becomes swollen into an ovoid or snbspherical shape, only the 

 neck region remaining normal. The tail disappears, its place 

 being taken by a terminal prominence carrying the vulva, 

 and the anus becomes dorsal in position. Cuticle striated, 

 without bristles. Head rather distinct, with six lips. Lateral 

 organs inconspicuous or absent. Stylet composed of three 

 rods, fused throughout and knobbed behind. Caudal end 

 of male without alae or papillae. Spicules equal, short and 

 broad. No accessory piece. Testis, in genotype, single, 

 anterior, outstretched. Female genital tubes paired, parallel, 

 anterior, elongate and sinuous. Oviparous, but eggs remain- 

 ing in the uterus after the death of the female hatch there 

 and the larvae escape later. Excretory system a lateral canal 

 on the left side only. 



Hab. Parasitic on roots of plants. 

 Genotype : H. schachtii Schmidt, 1871. 



Schmidt, 1871, Zeitschr. d.Ver. f. Riiben-Indust. in Zollverein, 

 xxi, 1-19 (not verified) ; Strubell, 1888, Bibliotheca Zool., 

 Cassel, i (2), 1-50; Railliet, 1896, Rec. Med. vet., Paris, 

 Ixxiii, 161 ; Marcinowski, 1909, Arb. k. Biol. An.st. f. Land- 

 u. Forstwirtsch., Berlin, vii, 147 ; Cobb, 1924, Journ. Para- 

 sitol, xi, 118, 120. 



The name Heterobolbus was proposed by Railliet to replace 

 Heterodera, on the ground that the name Heteroderes had previ- 

 ously been used by Latreille for another animal. This, how- 

 ever, does not seem to be a sufficient reason for abolishing 

 Heterodera. The name Caconema has been proposed by Cobb 

 for Heterodera radicicola (Greeif), but the author expresses 

 uncertainty as to whether it should be regarded as a distinct 

 genus or as a subgenus of Heterodera. The characters in which 

 it is said to differ from Heterodera s.s. are that it is " truly 

 endoparasitic and less specialized in its parasitism ; having 

 the amphids protected by ' cheeks ' ; the males with two testes, 

 instead of one as in H. schacJitii." 



5. Neraonchus Cobb, 1913. 



Cuticle finely striated, without bristles. Head not distinct, 

 without lips, papillae or bristles, but " helmeted " (presum- 

 ably with a specialized external cuticular cap). Lateral 

 organs unknown. Stylet relatively massive, in two portions, 

 the posterior much thicker than the anterior but not so well 

 chitinized, with knobbed base. Caudal end of male without 

 supplementary organs or papillae. Testes paired, parallel, 

 anterior, outstretched. Female genital tubes paired, opposed, 

 outstretched. 



