BUNONEMA INEQUALE 109 



Through the middle of the body the tubercles showed an obscure tendency to 

 group themselves in twos. 



Starting now at the other end of the body, the hindermost tubercle was a 

 broad flattish and rather inconspicuous affair, whose contour did not differ very 

 much from that of the remainder of the cuticle on the right side of the tail. This 

 posterior tubercle lay slightly in front of the anus. The penultimate and ante- 

 penultimate tubercles were rounded and closely resembled the majority of the 

 middle members of the series, though they differed in presenting more clearly 

 the subordinate minute tubercles on their surfaces. Here too, in some cases, it 

 was possible to demonstrate the presence of refractive elements perhaps nerve' 

 elements passing to the subsidiary tubercles. Behind the flattish posterior 

 tubercle the general character of the cuticle of the right side was maintained to 

 near the terminus, and the arrangement was such that the posterior extremity 

 appeared as if somewhat unequally bifurcated, one fork being the terminus 

 proper, that is, the end of the tail, the other being the slightly arcuate out- 

 turned loose terminal portion of the dexter cuticular armament. 



The lip region is a rather prominently expanded markedly asymmetrical struct- 

 ure. The flexibility of the neck enables the lip region to be swung with com- 

 parative rapidity back and forth through an angle of nearly ninety degrees. 

 There are six tapering, spreading, nearly straight cephalic setae, arranged in 

 very unequal pairs, a left submedian slender pair, one dorsally submedian, the 

 other ventrally submedian ; a large pair, correspondingly arranged, but extending 

 in the opposite direction, thus appearing to be right submedian; and a very small 

 right submedian pair. The members of the large pair are two to three times as 

 long as those of the left hand pair; these latter being about one-third as long as 

 the pharynx, whereas the former are more than halt as long as the pharnyx. 

 The right submedian setae are reduced and papilla-like. Each of these six setae 

 has a swollen or even bladder-like base, which is very much more pronounced in 

 the case of the largest setae. The dexter labial tubercle is located between the 

 two small right-hand setae. Between these latter and the larger setae there 

 may usually be seen two or three exceedingly delicate refractive elements some- 

 what suggestive of the repetitive elements in the nematode genus Wilsonemq; 

 these are beyond question connected with the largest setae. Between the left 

 submedian setae, that is to say, on the left lateral line, careful focusing shows in 

 the optical longitudinal section of the head what appears to be a minute pore, 

 ending in a depression on the outer surface of a minute labial elevation. On 

 each side of this "pore" are two minute papillae, corresponding to two similar 

 ones on the right side of the head. Between the left-hand setae and papillae 

 and the border of the mouth opening, there is a thin semi-circular, curved, pro- 

 jecting oral membrane, extending forward and outward. This membrane is wid- 

 est, that is, extends farthest forward, in the lateral region, and at this point its 

 altitude is somewhat less than the length of the left-hand setae. At their bases, 

 which are relatively broad, the setae are inflated, more especially the largest ones, 

 and are so set on the margin of the head that their proximal parts produce a very 

 pronounced shoulder. The rather narrow triquetrous pharynx, which ends 

 abruptly at the base, is of equal diameter throughout, and has a length about 

 equal to the diameter of the head measured opposite its base; it is entered through 

 a rather narrow mouth opening. The anterior end of the oesophagus receives the 



