NO. 6 CLASSIFICATION OF NEMATODES— FILIPJEV 23 



very similar to those of Enoplus. Synonchium (figs. 39-40) has 

 three of them, quite as in Enoplus, but it is, of course, nothing other 

 than a very evident case of convergence, no other character being ' 

 like that genus, whereas many characters resemble Cyatholaimits 

 or the other Choanolaiminae. 



The peculiar genus Richtersia (fig. 41) with its setaceous cuticle 

 shows similarities in its esophagus, its cuticle with the points, and its 

 spiral amphids, with the Cyatholaiminae, but it is advisable to place 

 it in a separate subfamily. 



A very large number of species, nearly infinite in their diversity, 

 must be included in the subfamily Chromadorinae. They are mostly 

 small and very variable in the structure of the cuticle, mouth capsule 

 and esophagus. All have only four cephalic setae and nearly all a 

 bulb and preanal papillae giving good diagnostic characters for dif- 

 ferent species. The amphid in some forms is a typical little spiral 

 lying very far forward (fig. 42), in others the abbreviation of the 

 head flattens the spiral which thus becomes the slitlike amphid typi- 

 cal for these other genera (fig. 43). 



The forms with the plain ringed cuticle consist of several sub- 

 families. The Desmodorinae have ordinary plain annules, without 

 any complications, and spiral amphids. The cuticle of the head is 

 generally strong and smooth, except in a few genera like Metachro- 

 niadora and Onyx which have a striation independent of that of the 

 body (fig. 44). Onyx has also a strongly developed spearlike tooth 

 and 12 well-isolated lips. 



The Monoposthiinae are characterized by a peculiar cuticle with 

 longitudinal rows of spines, in some forms fused into continuous 

 wings (fig. 45). Usually there is a round amphid, although several 

 forms have a spiral one. A very peculiar genus is Ceramonema, 

 placed here provisionally because of its cuticular rings (fig. 46). 

 The rings are very prominent and the amphid is horseshoe-shaped 

 instead of being spiral. The reduction of the mouth parts and a 

 very feeble onchium and buccal musculature should also be noted. 



The last two subfamilies are treated by many authors as a sep- 

 arate family or even an order, so aberrant are they in a general view. 

 Chaetosomatidae is the name most used for them, but Chaetosoma 

 being preoccupied, that family name also falls. The most remark- 

 able feature is the general form of the body with the swollen eso- 

 phageal part generally called the "head" followed by the thin "neck" 

 (figs. 47, 48), but the same form of the body, although not so well 

 developed, is found in several members of the Desmodorinae. The 



