84 NORTH AMERICAN 



following appearance when seen from the side : They appear to project 

 from the surface of the body very slightly, beginning as a tube having 

 a length about one-third as great as the corresponding diameter of the 

 head. This tube has very thin walls, and a short distance in, appar- 

 ently near the surface of the body, a second element appears in the 

 form of a circle inside that representing the contour of the outer tube. 

 This appears to constitute a sort of core in the midst of which are a 

 number of refractive elements, resembling nerve fibers, which pass in- 

 ward and backward toward the lumen of the oesophagus. Some of 

 these elements are longer than others. The focus passing inward picks 

 up one, then two, then several more, so that by the time a view is ob- 

 tained that is wholly inside the body there are seen a half dozen or 

 more of these elements. It is impossible in this view to pick up an in- 

 ternal connection of these refractive elements. The oesophagus begins 

 just below the transparent cuticle as a very narrow tube, probably not 

 more than one-eighth as wide as the corresponding portion of the neck. 

 It continues to have this diameter until after it passes through the nerve- 

 ring. At a distance from the nerve-ring equal to about one body diam- 

 eter, the oesophagus begins to change gradually into intestine. The 

 intestine gradually widens out, so that at a point as far behind the nerve- 

 ring as the neck is wide it has a width one-third as great as that of the 

 body. It goes on increasing in this way until at a distance from the 

 nerve ring three times as great it is two-fifths as wide as the body. 

 Near its middle the intestine is half as wide as the body. 

 The cells of the intestine contain granules of variable size, the largest 

 having a diameter fully twice as great as the thickness of the cuticle, 

 and the smallest being very minute. The female has not been seen. 

 The tail of the male is slightly arcuate, and is conoid to the blunt, 

 rounded terminus, which has a diameter half as great as that of the 

 base of the tail. There is no spinneret, and there are no caudal glands. 

 The lateral fields are about one-third as wide as the body. The nerve- 

 ring surrounds the oesophagus somewhat obliquely. Nothing is known 

 concerning the ventral glands or the excretory pore. The tail of the 

 male bears several series of innervated papillae. These are sufficiently 

 elevated at the surface of the cuticle to slightly break the contour when 

 the tail is seen in exact profile. Where each nerve passes through the 

 cuticle there is a very low, almost imperceptible elevation at the sur- 

 face. These papillae are arranged on the ventral submedian lines as 

 well as on the ventral line. The ventral papillae just in front of and 

 just behind the anus are double. As to particulars of the submedian 

 group, there are four on the tail, one member opposite the anus; one 

 a little farther back, a third near the middle of the tail, and a fourth 

 considerably farther back. In front of the anus on each side are eight 

 submedian papillae. These occupy a distance more than twice as great as 

 the length of the tail, and the distance between successive papillae in- 



