13G ASCAROIDEA 



The cephalic bristles are highly developed, those in the 

 posterior crown being extremely long and tentacle-like. 



Hab. Marine. 



Genotype : T. barbata Ditlevsen, 1919. 



Ditlevsen, 1919, Vid. Medd. Naturh. Foren., Copenhagen, 

 Ixx, 181. 



19. Discophora Villot, 1875, nee Boisduval, 1836. 



This genus is very vaguely defined by Villot. The following 

 characters are taken from Eberth's description and figures of 

 the genotjrpe : — 



Cuticle smooth, with short lateral rows of bristles in the 

 neck region. Head not distinct. Mouth with three small 

 papillae. Head strengthened internally by a pair of lateral 

 plates, each having two perforations. Oesophagus simple, 

 club-shaped. Ocelli present. Male with a pair of rather 

 stout sickle-shaped spicules and a small accessory piece with 

 a posterior process. Female genital tubes paired, opposed. 

 Spinneret present. 



Hab. Marine. 



Genotype : D. [Enoplus] cirrJiatus (Eberth, 1863). 



Eberth, 1863, Untersuchungen iiber Nematoderi, Leipzig, 34 ; 

 Villot, 1875, Arch. Zool. exp. et gen., iv, 463. 



The armature of the head seems to suggest that this genus 

 may be related to Thoracostoma. Eberth describes the lateral 

 plates as belonging to the " pharynx," but this organ is not 

 otherwise described. The validity of the genus being some- 

 what doubtful, we do not suggest a new name for it. 



20. Onyx Cobb, 1891. 



Cuticle finely striated. Head rounded, with retractile lips 

 ( ? twelve) and pointed papillae. Lateral organs large, spiral. 

 Pharynx contains a spear-like tooth attached to its dorsal 

 wall, and a threefold growth from the walls of the anterior 

 part of the pharjoix acts as guide for this tooth. Oesophagus 

 with narrow anterior half and stouter, nearly cylindrical, 

 posterior half. Caudal end of male with a single, bristle- 

 bearing, ventral postanal papilla, and a number of ventral 

 preanal supplementary organs. Two accessory pieces present. 

 Testes paired, opposed, sometimes reflexed at ends. Female 

 genital tubes paired, opposed, reflexed. Caudal glands 

 present. 



Hab. Marine (in sand). 



Genotjqje : 0. perfectus Cobb, 1891. 



Cobb, 1891, Proc. Linn. Soc. N.S.W., Sydney, vi, 146. 



