1906.] NATURAL SCIENCES OF PHILADELPHIA. 243 



rounded by a rugous, furrowed lip. Just behind this lip is a shallow 

 transverse ventral groove, while near its posterior end this segment is 

 completely encircled by another faint furrow which, like the groove 

 mentioned, is met by the longitudinal furrow on each side. 



Besides the pygidium the type has 24 segments, while the only other 

 complete specimen in the collection has 25. The peristomium is 

 achsetous, and somites II to XXII (or XXIII) inclusive are setigerous, 

 leaving two preanal achsetous segments, as in N. lumbricalis. Somite 

 II is as long as the head ; the next seven or eight segments are succes- 

 sively of slightly increased length, the last named being nearly twice as 

 long as the first. Behind IX several segments remain nearly equal in 

 length, then the length diminishes, at first slowly, then rapidly to the 

 last, the last three setigerous segments each equalling III in length and 

 the two achsetous preanal segments together barely exceeding the last 

 setigerous. Somites II, III and IV are of much greater diameter an- 

 teriorly, and slope to the posterior end which is inserted slightly into 

 the next succeeding segment. The next five segments (V to IX) are 

 more nearly cyhndrical, but bear slightly produced glandular collars at 

 their anterior ends. The last four are simple short rings. At the two 

 ends of the body the intersegmental furrows are deep and distinct, but 

 in the middle region they are obscure. 



The pygidium is funnel-form, but little widened, regular and some- 

 what longer than the last two segments combined. On the type its 

 margin is divided into twenty-one equal and regular triangular teeth 

 each with a minute cirriform tip. The only other anal funnel present 

 has but sixteen marginal teeth and cirri. The anus is central and very 

 large, and is surrounded by about ten regular lobes separated by as 

 many radiating furrows. At about somite VIII the neural groove 

 begins to be distinct between the lateral muscle ridges and continues 

 to XXIV, from which point a faint neural line continues across the 

 pygidium to end in the median marginal tooth which is narrower than 

 the others. The other anal funnel has the three median ventral teeth 

 smaller and the nerve cord terminating between two of them. 



No distinctly elevated tori or setigerous tubercles exist anterior to 

 XIII, on which the latter are midway between dorsum and venter, 

 And the ridge-like tori extend from just below them through the centre 

 of the broad glandular zone nearly to the neural line. On succeeding 

 segments they are even more prominent, and behind XV have shifted 

 with the glandular zone to the posterior end of the segment. Toward 

 the posterior end as the thin-walled portion of the segment diminishes 

 ih length they become more central, and finally on XXI and XXII the 



