110 ASCAROIDEA 



have been unable to accept the remainder. The subfamily 

 Anguillulinae contained only Anguillula and Macrolaimus, 

 which seem to us to fall more naturally into the family Rhab- 

 ditidae (subfam. Rhabditinae). There seems to be nothing 

 to prevent the contents of the subfamily Diplogasterinae also 

 from being transferred to the same position in the system. 

 The Microlaiminae and Chromadorinae are so vaguely defined 

 as to be incapable of separation from each other or from the 

 Oncholaiminae. On the other hand, there seems to be some 

 justification for grouping together certain forms in which the 

 pharynx contains only a single, frequently stylet-like, dorsal 

 tooth, the other teeth characteristic of the family being 

 absent. Accordingly, we have placed these genera in a new 

 subfamily, Desmodorinae. 



As regards the family name, it is not in accordance with 

 existing rules to take as the tj^pe of a family a genus which 

 is not also the type of one of its subfamilies. We have 

 therefore substituted the name Oncholaimidae for Odonto- 

 pharjmgidae. 



The provisional classification here outlined is admittedly 

 far from satisfactory. It is based chiefly upon the characters 

 of the buccal cavity, which, in accordance with the plan 

 adopted throughout the system, we have taken to be of 

 primary importance. The groups, however, grade into each 

 other almost imperceptibly, and it is possible to connect them 

 at various points with other families. In an ideal, or 

 " natural," system of classification the genera would be 

 better arranged in the form of a genealogical tree, and this 

 would probably bear very little relation to the arbitrary and 

 artificial system into which we have attempted to fit them. 



Subfam. 1. ONCHOLAIMINAE Micoletzky, 1922. 



Pharjmx typically rather spacious, containing three teeth, 

 frequently at or near its base. One or more of the teeth 

 may be lost, or additional teeth may be developed on the 

 walls of the pharynx. Oesophagus typically club-shaped, 

 exceptionally with a posterior bulb. 



1. Oncholaimus Dujardin, 1845. 



Syn. Viscosia de Man, 1890; Metoncholaimus Filipjev, 

 1918; Adoncholaimus Filipjev, 1918; Prooncholaimus Mico- 

 letzky, 1924. 



Some species of relatively large size (25 to 30 mm.). Cuticle 

 unstriated, sometimes glutinous. Bristles usually present 

 on the tail and papillae or bristles frequently present towards 

 both extremities. Head not distinct, with rounded lips, and 

 usually with bristles. Lateral organs transversely elliptical. 



