UNGELLA SECTA 



n.gen. n. sp. 



A nemic parasite of the Burmese Oligochaete (earthworm), 

 Eutyphoeus rarus. 



CONTRIBUTIONS TO A SCIENCE OF NEMATOLOGY XVIII 

 BY N. A. COBB 



Ungella secta n. gen. n. sp. 



The transparent colorless cuticle is traversed by transverse striae, about 

 one micron apart, hard to resolve even with high powers, at least in alcoholic 

 specimens. In certain stages of the nema the striae are 

 much more (obvious and double [in jsize. Though inter- 

 rupted, the striae are not altered, on the lateral fields, 

 where there are only faint single wings non-existent or 

 faint on the neck and anterior portion of the body, but 

 somewhat readily seen along the middle of the body. The 

 very slightly oblique longitudinal striae, due to the at- 

 tachment of the musculature, are more readily visible than 

 the transverse striae. (Fig. 3, str longt) Between the 

 longitudinal striae are faint rows of dots, reminiscent of 

 the cuticular markings of Diplogaster, 



And here it may be said that, though valveless, the 

 oesophagus also is reminiscent of Diplogaster; and that 

 of all the free-living genera, Diplogaster is that to which 

 Ungella seems most closely related. It is readily conceiv- 

 able that the submedian duplex onchium (Fig. 1), could 

 have been evolved from an armature such as characterizes 

 one of the types of diplogastric pharynx. 



Onchium. The duplex onchium of Ungella has its amalga- 

 mated roots mo vably imbedded in the head end of the nema 

 backward for a distance equal to two-thirds the width of 

 the head or mo re, 'it is assumed therefore that this represents 

 the depth of the otherwise unarmed pharynx. The onchium, 

 which can be exserted for the greater part of its length, is a strong refractive 

 organ, colorless except distally, where it is yellowish; it is a conspicuous feature 

 of the head, especially when protruded. The two equal claws of the onchium 

 are joined rigidly in such a way as to make it impossible for them to be juxta- 

 posed, and their internal structure makes plain that they represent the two 

 ventrally submedian sectors of the oesophagus. Thus the onchium and its 



Fig. 1. Ungella 

 secta. Side, dorsal 

 and end views of 

 the same head. 

 M'br, the intussus- 

 ception membrane. 



Waverly Press, Baltimore, Md., June 19, 1928. From Jour. Wash. Acad. Sc., Apr. 4, 1928. Repaged without 

 material alterations. 



