MERMITHIDAE 63 



1. Laxonema Cobb, 1920. 



Cuticle coarsely striated, with irregularly-distributed 

 bristles, and without lateral alae. Cuticle of head radially 

 striated, with four bristles and a double crown of papillae. 

 Lateral organs tubular, open in front. Buccal capsule very 

 small. Oesophagus with pjTiform posterior bulb. Caudal 

 end of male with minute longitudinal striations, without 

 supplementary organs or caudal papillae. Spicules rather 

 stout. An accessory piece present. Testis single, out- 

 stretched. Caudal glands and spinneret present. Female 

 unknown. 



Hab. Marine. 



Genotype : L. majum Cobb, 1920 [rectius majus]. 



Cobb, 1920, Contr. Sci. Nematol., ix, 243 and key. 



m, Pararhabditis, nom. nov. 



Syn. Pseudorhabditis Sziits, 1912, nee Perroncito, 1880. 



Body tapering towards each end. Head " pointed in the 

 manner of a ninepin," with three naked lips. Cuticle longitu- 

 dinally striated. Anterior portion of body covered thickly 

 with curved, backwardly-directed spines, extending in con- 

 stantly thinning rows to the middle of the body. Buccal 

 cavity tubular, wide. Oesophagus with an oval median and 

 a club-shaped posterior bulb. Vulva in posterior region of 

 body. Female genital tubes symmetrical. 



Hab. Parasitic in an Earthworm. 



Genotype : P. [Pseudorhabditis] entzi Sziits, 1912. 



Sziits, 1912, Allatt. Kozlem., Budapest, xi, 82. 



Fam. 8. MERMITHIDAE Braun, 1883. 



Greatly elongate and generally relatively slender forms (in 

 the adult condition), with a smooth cuticle, frequently con- 

 taining spiral fibres which run through it in criss-cross direc- 

 tions. Head usually with two lateral and four submedian 

 papiUae, and often with additional small circumoral papiUae. 

 A pair of lateral organs always present, usually well developed. 

 Alimentary canal complete only in the larvae. In the early 

 larval stage the mouth is provided with a piercing stylet, 

 which is lost after penetration into the host. In the adults 

 the oesophagus becomes reduced to a simple, narrow, cuticular 

 tube, and the intestine becomes modified into a sausage- 

 shaped, solid fat-body, without an anal opening. Genital 

 tubes usually paired in both sexes. Caudal end of male 

 without alae, but usually with three longitudinal rows of 

 papiUae. A pair of spicules or a single spicule present. Vulva 

 at about the middle of the body. Vagina short and muscular, 



