2y CAI.irolIMA ACADK.MV I'l' SCIICNCES. 



oiifo, ill wliicli it ilifTcr.^ frmn tlie corrcsiioiiding orfi;:iii nf the two other species de- 

 sciilxd licic. 



Septal (jlands (fig. 1). The septal glands of the n'?;ophiign« are foniid jiaircil in 

 somites vi, vii, viii and ix. They arc all comparatively small and very thin and 

 Hat. The posterior ones are smaller, Imi tlic dillVrcnce hetween the glands is not 

 so great as for in.stance in some species of Ocnerodriliis, or as in DuUnnin Troycri. 

 They are more nearly of the same size, and they extend all around the o'sophagii.s 

 and arc more or less divided in several separat<' lolics. Wc can, however, always 

 distinguish one pair in each somite connected witii the septnm hidow the alimentary 

 canal, extending upward with its free upper lohes, which do not connect. 



Nephridvt (figs. 11) and IJO). 'i'hc iicpiiridia cDnunciice in somite ii, an<l are 

 found in all po-tciior somites. The thice anterior nephridia — in ii, iii and iv — arc 

 slightly dift'erent as to size and mitward form, and may he considered as a kind of 

 pepto-ncphridia. They open, also, difi'crently fnjm other nephridia, their pores 

 being in front of and a little interior (nearer the ventral ganglion) to seta 4, while 

 all other nephridia open in front of and interior to the third seta. The nephridio- 

 pores of the clitellnm are considerably larger than the purcs in the other somites, and 

 appear like large, transparent discs when viewed from the outside. All nephridia 

 possess a vesicle or bladder next to tiic body-wall. A small collar of tubular cells 

 surround the nephridio-pore. The vesicle is smaller in the anterior pe|)to-ncpbridia, 

 gra(hially increasing in size backwai'd, l)eing largest in the post-clitcllar nephridia, 

 where it is several times larger than in the pcpto-nephridia. In the three pairs of 

 |Hpt(>-ncphiidia, the vesicles are almost circular, and of the same size in the three ne- 

 phridia. That of the first common nephridium in somite v is of about the same size 

 us the pepto-nephridial vesicles, but from this on the bladders increase gradually, hut 

 slowlv, in size to the end nf the clilellinu. J'>ut in somite xviii and following to the 

 end of the body, the vc^sicles are niiicli largei-, about twice as large as those in the 

 clitellnm. Tims the ne|)hi'idio-vcsieh's in the ciitelhnii ai-e about three to four times 

 shorter than the tnl)idar pai-t, while the post-cditellar vcsi(dcs are half, or more than 

 half, as long as the tubulai- part or duct, when oidinarily folded, in the pepto- 

 nephridia, the vesicle is about five times shorter tiian the folded tube, and the tubular 

 duct extends more backward than in the other nephridia — esi)ecially .so in the first 

 nephridium — encroaching on the next posterior somite, reaching diagonally across the 

 somite, while all the other nephridia run paialhd with the inlcrsi-gmcntal grooves. 

 This diagonal position of the nephridia is, however, not always constant, except in 

 the most anterior nephridium. The vesicle in the posterior nephridia consists of two 

 more or less distinct lobes, the posterior one (to the duct), which is more rounded 

 and bladder-like, forming a co'cum, and the anterior, which is elongated or deltoid. 

 This difference is more pronounced in the [losterior than in the anterior nephridia. 

 most so in the nej)hridium in soiute xviii, which nephridium is generally the largest 

 of all. From this somite the nephridia diminish somewhat in size, both anteriorlv 

 and posteriorly. The posterior margin nf the vesicle is considerably lobed. and in 



