ANGUILLULININAE 67 



is no functional anus. (2) Tiie excretory pore is near the 

 middle of the body. (3) The male has no caudal alae. (4) 

 The male " practically loses the spear at the final moult." 

 (5) The posterior portion of the body of the female becomes 

 sac-like at maturity, and its cuticle much thickened. (6) The 

 vulva is situated in a deep " suture." 



Hab. Parasitic on the roots of Citrus trees. 

 Genotype : T. semi -penetrans Cobb, 1913. 



Cobb, 1913, Journ. Washington Acad. Sci., iii, 288; 1914, 

 Journ. Agric. Res., Washington, ii, 217. 



3. Aphelenchus Bastian, 1865. 



Syn. Paraphelenchus Micoletzky, 1922 ; Chitinoaphelenchus 

 Micoletzky, 1922. 



Cuticle usually striated, without bristles. Lateral alae 

 sometimes well developed. Head usually distinct, knob-like, 

 without lips or bristles. Cephalic papillae rarely distinct. 

 Lateral organs unknown. Stylet composed of three fused 

 rods, not always distinctly knobbed behind. Caudal end of 

 male without alae, usually with postanal papillae and some- 

 times with preanal papiUae. Spicules slender. A slight 

 accessory piece often present, sometimes composed of three 

 fused pieces, two dorsal and one ventral, and usually with 

 an expanded, handle-like inner end. Female genital tubes 

 typically paired, opposed, outstretched, but with posterior 

 branch of uterus vestigial and without ovary. Spinneret 

 apparently absent. 



Hab. Chiefly in soil, about roots of plants. Some species in 

 fresh water, in decaying substances, or parasitic on plants. 

 Genotype : A. avenae Bastian, 1865. 



Bastian, 1865, Trans. Linn. Soc. London, xxv, 93, 121 ; 

 Micoletzky, 1922, Arch. f. Naturg., Abt. A, Ixxxvii, 584. 



Micoletzky (1922) proposes to divide this genus into three 

 subgenera, Ap>helenchus, Paraphelenchus and Chitinoaphelen- 

 chus. Paraphelenchus is intended to contain three species in 

 which the oesophagus is marked off from the intestine more 

 distinctly than in typical forms, while Chitinoaphelenchus 

 contains only two species, characterized by " chitinous orna- 

 mentation " of the anterior end. These peculiarities are so 

 slight that they scarcely seem to warrant the erection of 

 special subgenera. The distinctions between Aphelenchus 

 and Anguillulina do not appear to be very definite. 



4. Heterodera Schmidt, 1871. 



Syn. Meloidogi/ne Goldi, 1889; i/eiero6oZ6ws Railliet, 1896 ; 

 Caconema Cobb, 1924. 



