STRUCTURE OE THE EXCRETORY ORGANS OF AMl’KIOXUS. 185 
On the Structure of the Excretory Organs of 
Amphioxus. 
Part 2. — The Nephridium in the Adult. Part 3. — Hatschek’s 
Nephridium. Part 4. — The Nephridium in the Larva. 
By 
Edwin S. Ciioo€li‘i<-li, F.IC.K., 
Fellow of Merton College, Oxford. 
With Plates 11 — 16, and 1 Text-figure. 
Part 2. — The Nephridium in the Adult. 
In Part 1 of this contribution, which appeared some years 
ago (7), it was shown that the nephridia of Amphioxus bear 
a startling resemblance to the nephridia of certain Polychaete 
worms, such as Phyllodice ; they are segmental, they are 
formed of an excretory canal opening to the exterior (atrium), 
but ending internally in blind branches; these blind ends are 
provided with typical solenocytes. The last fact was the only 
striking novelty then contributed to the descriptions of Weiss 
(13) and Boveri (1). Although I can now add but little of 
real importance to my previous account, it is necessary to 
return to the subject again owing to the publication by 
various authors of certain statements as to the presence of 
internal openings. These statements, if not soon disproved, 
will spread confusion and error in the literature of the subject 
which it may take years to eradicate. Had not other pressing 
work prevented me, I should myself long ago have attempted 
