112 ASYMMETRY OF THE NEMATODE 



of this lateral protuberance there is a rounded innervated papilla, which breaks 

 the contour of the curved line between the protuberance and the adjacent seta. 

 On the lateral line opposite the base of the protuberance there seems to be a 

 third papilla of the same character as the two last described. The head is sepa- 

 rated from the neck by a very distinct constriction. Where the somatic cuticle 

 ends, a little in tront of the middle of the pharynx, there is a rather distinct 

 shoulder, and from this shoulder the diameter decreases rapidly to the base of 

 the lips opposite the anterior end of the chitinous portion of the pharynx. Here 

 the diameter is only about three-fifths as great as at the shoulder before men- 

 tioned. The saccate basal portions of the large apparently dextral setae extend 

 backward somewhat from the collum or constriction separating the lip region 

 from the neck. Viewed from the left side the left submedian setae are' seen to 

 be not inflated at the base. Three labial papillae are also to be seen from this 

 side, one lateral and two submedian. These, together with those seen on the 

 right side, complete the complement of six minute and very inconspicuous labial 

 papillae encircling the head. Th,ere is no forward-pointing thin semicircular 

 border to the mouth opening, as in inequale. The pharynx is triquetrous, and 

 about as long as the posterior bulb, or a little longer, in other words about one 

 and one-third times as long as the diameter of the head measured opposite the 

 base of the pharynx. As seen in optical longitudinal section the pharynx is about 

 one-sixth to one-eighth as wide as long. Its cross-section is somewhat similar 

 to that of the oesophagus; in other words, it is not prismoid, and yet is more or 

 less triquetrous; each of the angles is composed of a thin, refractive, simple, chi- 

 tinous element. The mouth opening is hardly wider than the pharynx. There 

 are one or two innervated papillae on the dorsal side of the tail near the rectum. 

 Nothing is known concerning the female sexual organs, but from the rudiments 

 seen in male specimens which probably have yet to undergo a final moult, it seems 

 clear that the testis is single and has its blind end reflexed a distance about equal 

 to the diameter of the body. 



Habitat. Found with Bunonema inequale in the rotting wood of red oak. 

 Bunonema impar is very closely related to Bunonema inequale, and may indeed 

 prove to be merely a variety of that species. 



3. Bunonema dactylicum, n. sp. Species with about the same dimensions and 

 form as the two preceding. As only the young forms have been seen it remains 

 somewhat uncertain whether the thickened dextral cuticle 

 bears tubercles, but i1 is believed not. The cuticle is tessel- 

 lated and striated as in the first species described. The two 

 large saccate setae are arranged very much as in B. inequale, 

 and there is a dextral labial "tubercle" as in that species. 

 The left submedian appendages are palmate, as shown in 

 Figure 2, and have about five finger-shaped processes. In- 

 side the saccate setae is a forward-pointing, more slender 

 pair of equal length. 



Head of Habitat. Found in the rotting wood of red oak, with the 

 n a dactylicum, two preceding, Washington, D. C., U. S. A. 



n. sp. 



May, 1915 



