64 NORTH AMERICAN 



somewhat dotlike elements. These striae are more readily visible toward 

 the extremities, especially the posterior extremity. The conoid neck becomes 

 convex-conoid toward the head, which is somewhat rounded. Throughout 

 the body there are rather numerous, long, slender somatic setae having a 

 length equal to the radius of the body. These setae are a little longer toward 

 the extremities than they are near the middle of the body. On the outer 

 margin of the head, a trifle in front of the base of the pharynx, there are 

 ten spreading, tapering cephalic setae, one on each lateral line, and two of 

 somewhat unequal size on each submedian line. The longest of these setae 

 are more than half as long as the head is wide. A little more than twice as 

 far back as the amphids there is a rather definite circlet of cervical or sub- 

 cephalic setae arranged in submedian positions. The lips appear to be three 

 in number, and are longitudinally striated or fluted. The thin flap-like, stri- 

 ated portions are capable of assuming a revolute position. The basal por- 

 tion of the lip region is considerably thicker than the flaps, and is arched 

 over the margin of the pharynx. This latter is wide and shallow. Just 

 beneath the lips it is two-thirds as wide as the front of the head. It closes 

 together rapidly, so that its base is located at a distance from the anterior 

 extremity about equal to the radius of the head. In other words, the pos- 

 terior portion of the pharynx is about half way back to the amphids. These 

 latter are circular, and one-third to one-fourth as wide as the correspond- 

 ing portion of the head. Their distance from the anterior extremity is about 

 equal to half the width of the front of the head. A short distance in front 

 of each amphid there is a granular nucleus, which closely resembles the 

 nerve cells that are found in the neck, and seems doubtless to be the nucleus 

 of the nerve cell which is connected in some way with the function of the 

 amphids. The oesophagus reaches to the base of the lips, and into it is set 

 the posterior portion of the pharynx. At first the oesophagus is only two- 

 thirds as wide as the base of the head. It continues to have this diameter, or 

 a little more, until after it passes through the nerve-ring. Thence onward it 

 gradually increases so that finally it is about two-thirds as wide as the base 

 of the neck. The lining of the oesophagus is a fairly distinct feature. The 

 intestine, which is separated from the oesophagus by a distinct constriction, 

 is composed of cells of such a size that probably six to eight are required to 

 build a circumference. The anterior portion of the intestine is somewhat 

 bulbous in form, and is separated from the oesophagus on the one side and 

 the true intestine on the other, by a pair of constrictions. This portion may 

 be looked upon as a strongly developed cardia. The intestine is moderately 

 thick walled, and ends posteriorly in a short, wide rectum, hardly as long as 

 the anal body diameter. The posterior extremity of the female begins to 

 taper from near the vulva, and continues to taper at about the same rate 

 behind the tail as in front of it. The tail itself is conoid in the anterior four- 

 fifths, and cylindroid in the posterior fifth. The terminus is hardly swollen, 

 and is about one-sixth as wide as the base of the tail. The spinneret is 

 rounded and bears a couple of submedian setae twice as long as its own 



