I ) S rSKRIFT FÖR l.II.LJEBORG 



Pontoscolex Lilljeborgi n. sp. 



Definition. Length 40 mm., widest diameter 2 mm. Number of somites 

 164. :<r bifid at apex, not ornamented. Qitellar seta not known. Prostomium very 

 Caudal zone 1 2 to 19 somites from the tail end. Hearts in xi and xii. Calci- 

 us diverticula in vii, viii and ix. Spermatheca three pairs, in viii, ix, x, sac-like, 

 without narrow duel; spermathecal pures open in front of the septa in the posterior 

 part of the somites viii, ix, x, in line with setcc a and b. Nephropores in line with 

 seta i . testes in xi. 



Habitat: Antigua in Guatemala. 



Exterior characters. Pontoscolex Lilljeborgi is a small species wholly 

 aquatic and almost as pellucid as glass. My description is based on six specimens 

 in rather poor preservation on account of maceration. This will account for the 

 incompleteness of the details given. I believe however that enough is known to 

 define the species and to show that we here have a form not previously described. 



Somites. The first eight somites are much larger than those following, 

 the clitellar ones being imperfectly developed or in degeneration. 



The anterior twelve to thirteen somites are all three-ringed, the following 

 ones are only indistinctly so. Prostomium is present, very long, pointed and exceed- 

 ingly prominent in several of the specimens. In one specimen it was fully extended 

 (fig. 1), in the other less so, but it was always distinct. Setae begin in somite ii. 



Setae. The anterior couples are strictly paired. The ventral couples, or 

 a and b, are paired in the anterior somites. In somite xi setae a and b begin 

 to separate and reach their final distance about somite xxv, which distance is thence 

 kept up until about somite xxvii. As far as this somite, then, the setae a and b 

 r< spectively have run in a continuous row, the two rows being first deltoid and then 

 parallel. About somite xxvii setae b become irregularly placed, while setae a con- 

 tinue in one row. Seta: c and (/again are strictly paired in the anterior ten somites. 

 In xi the setae d separate slightly, and in the following somites setae d are irreg- 

 ularly placed. About somite ex the setae a also begin to be irregularly placed, and 

 about exx tluy are entirely so. The regular setae are in no way ornamented, but 



-lightly bifid. The anterior setae are smaller, but about in the sixteenth 



somite from the tail the setae begin to increase in size and also become less sigmoid. 



But the dorsal setae increase much more rapidly than do the ventral setae, reaching 



P "-'• ''i about the sixth somite from the tail. Here, as in the setae of 



caudal segments, the dorsal setae are the largest, the ventral ones the smallest, 



ind those between are intermediate in size. Comparing the largest of the posterior 



