THE 



ASYMMETRY OF THE NEMATODE 

 Bunonema iiiequale, n.sp. 



BY N. A. COBB 

 CONTRIBUTIONS TO A SCIENCE OF NEMATOLOGY, III 



The genus Bunonema was established in 1905 by Dr. L. A. Jagers- 

 kiold for the reception of species from Kerguelen Island and from 

 the Schwarzwald. 1 Recently species belonging to this genus have 

 been found in Switzerland and examined by Dr. G. Steiner. 2 



The present account deals with species found at Washington, 

 D. C., U. S. A., in the rotting wood of red oak. The specimens have 

 been examined with considerable care on account of their remarkable 

 asymmetry. It seems probable that this asymmetry is characteristic 

 of the genus. The following is an extended description of the generic 

 characters of Bunonema. 



BUNONEMA Jagerskiold 1905 



The rather thin layers of the transparent naked cuticle are tra- 

 versed by four hundred to five hundred transverse striae, rather diffi- 

 cult of resolution. In at least a part of the circumference the annules 

 are resolvable into dot-like elements, which apparently are the ends 

 of minute, radial, rod-like elements in the cuticle. These elements 

 are so arranged, at least on the right side of the body, as to give rise 

 to a tessellation, in the midst of which, on the lateral field, there is 

 usually a longitudinal series of tubercles of relatively large size, ar- 

 ranged in one or two rows, extending from near the head to near 

 the terminus. When two rows of tubercles are present, one or more 

 pairs at each end of the series are likely to be combined into a single 

 tubercle. When viewed en face the surface of these tubercles pre- 

 sents a punctate appearance, and their circumferences not infre- 

 quently show the presence of minute papilla-like elements, which do 

 not break the contour, but which appear to have passing to them, 

 from the body wall, linear elements, suggesting that the tubercles 

 are innervated. When seen in profile the tubercles appear to be made 



1 "Bunonema richtersi, n. g., n. sp.," Zoologischer Anzeiger, 28 February, 1905. 



2 "Freilebende Nematoden aus der Schweiz," Archiv fur Hydrobiologie und 

 Planktonkunde, 1913-14. 



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