XANTHODORA 317 



98. Xanthodora nuda n. sp. The striae of the yellow, naked cuticle have the 

 appearance of a series of hoops that are considerably wider on the neck, espe- 

 cially toward the head. The anterior half of the neck is convex-conoid, the 

 convexity increasing steadily toward the head. From the point where the 



striae cease on the head, the cuticle diminishes 

 i'|- '" -^Y ''^V y 8 -> 2 -2- very rapidly in thickness, so that opposite the 



dorsal tooth, it is not more than one-third as 

 I'.l ' ' 3*5 ' 'Ts " " ?j >' 9 ->2- " thick as a little farther back; thence onward, it 



is thin to a point half way between the circlet of 



setae and the axis of the mouth opening. At this point, the hard cuticle ceases 

 and there is a very minute, faint groove encircling the lip-region. The lips come 

 together so as to form a vestibule having a width about one-third as great as the 

 diameter of the circlet of setae. The tissues of the lips apparently reach back a 

 little farther than the apex of the dorsal tooth, and their limits are rather easily 

 noted on account of the fact that they attract carmine stain more than the 

 surrounding tissues do. The lip-region appears to be longitudinally striated 

 internally, and probably to consist of about a dozen elements folded together. 

 When the mouth is open and the onchium thrust forward, the labial region is 

 seen to be practically continuous and entire on its anterior margin, from which 

 it follows that any striations appearing when the mouth is closed are due to 

 foldings of the lip-region. When the mouth is open and the lips expanded, the 

 amphids become more nearly circular. When the lips are closed, the vestibule 

 widens out but little in front of the dorsal tooth, whose apex lies in the axis of 

 the vestibule. The pharynx is surrounded by muscles which appertain particu- 

 larly to it, as is indicated by the fact that they are separated from the oesoph- 

 agus by a broad but fairly distinct constriction. The oesophagus continues to 

 have the same diameter until near the nerve-ring, where it diminishes somewhat 

 in diameter. Very soon after passing through the nerve-ring, it enlarges, some- 

 times rather suddenly, to form the elongated posterior three-fifths of the organ. 

 This enlarged part averages to be about 

 three-fifths as wide as the corresponding por- 

 tion of the neck, and contains a massive lin- 

 ing, which, when viewed in optical section, 

 occupies one-fifth of the diameter. This 

 enlarged portion of the oesophagus is divided 

 into three regions by breaks in its radial mus- 

 culature, of which one region comprises 

 nearly the whole of the anterior half. The 

 other two parts are of subequal size. Though 

 the lining of the oesophagus is quite distinct . 

 in the narrow portion, it is considerably less 

 so in the wider portion, and ceases a short 

 distance in front of the posterior end of the P 

 oesophagus. Cardiac collum less than one- 

 third as wide as the base of the neck. For a $? 

 short distance, the intestine is composed of small cells differing from those which 

 make up its main part. These cells stain more strongly with carmine and con- 

 tain nuclei of relatively larger size. This region probably may be regarded as a 

 sort of cardia. The intestine becomes almost at once two-fifths as wide as the 

 body. Its cross-section would present about eight cells. The cells are packed 



