250 J. T. CUNNINGHAM. 



been observed by Edouard Meyer of the Zoological Station at 

 Naples ; and his discovery is mentioned by his permission in a 

 single sentence in Lang's ' Monograph on the Polycladen,' 

 published in 1884. 1 But the accessible information concerning 

 these organs in this species is so inadequate, that R. S. Bergh, 2 

 in a general review of the excretory system in worms, cites 

 both Lang's mention of Meyer's observation and Cosmovicr's 

 account of the organs as if they were both equally correct. 



The true relations of the excretory system are as follows : — 

 Enumerating the somites from before backwards, and counting 

 the buccal as the first, we find that the branchiae belong to 

 somites n, in, and iv : the first notopodial fascicle of capillary 

 chaetae is on the fourth somite, the third branchiferous j the first 

 neuropodial uncinigerous torus is on the fifth ; the neuropodial 

 tori are repeated on every succeeding somite to the end of the 

 body ; the notopodial fascicles occur only on seventeen consecu- 

 tive somites. There are traces of transverse septa behind the first, 

 second, third, and fourth somites, but none in the rest of the 

 thoracic region, which bears the" notopodial fascicles. On dis- 

 section, four long double nephridial tubes are seen projecting 

 dorsalwards into the body cavity; the lower parts of these tubes 

 are covered by strands of the oblique muscles which pass from 

 the nerve-cord to the neighbourhood of the notopodial bristles ; 

 careful examination shows that these tubes belong to somites vi, 

 vn, vin, and ix. Their internal openings can be found imme- 

 diately behind the fascicle of bristles belonging to somites v, vi, 

 vn, and vin respectively, but their efferent tubes are seen to pass 

 down beneath the fascicle of somites vi, vn, vin, and ix. The 

 lower parts of these efferent tubes are very wide, and it is impos- 

 sible to separate them from one another. Beneath the fascicles of 

 the following four somites (x to xni inclusive) are seen membra- 

 nous nephridial sacs, which externally at least are inseparable 

 from one another. These sacs are simple, that is, they are not 

 composed of a tube bent on itself like the anterior nephridia ; 

 they scarcely extend above the level of the oblique muscles, and 



1 ' Fauna u. Flora des Golfes von Neapel,' xi Monographie. 

 - 'Die Exkretious-organe der Wiirmer ' Kosmos, Bd. ii, 1885. 



