494 EDWIN S. GOODR[OH. 



subjects. It will be necessary only to deal in detail here 

 with certain points on wliich we differ, and concerning which 

 I am able to correct Boveri's account in some important 

 particulars. 



The following is a brief statement of Boveri's description 

 of the excretory organs : — Each consists of a tubule ciliated 

 internally, and opening into the atrium by a pore near the 

 top of the secondary gill-bar. In the mid-region of the 

 pharynx, where the canal is best developed, it extends 

 forwards to near the origin of the primary bar in front, and 

 backwards to the primary bar behind, down which it runs 

 for some little distance. Along its course the tubule is said 

 to open iuto the dorsal coelom by means of a varying number 

 of small funnels ; and spread over the coslomic wall in the 

 neighbourhood of each funnel are many peculiar pin-shaped 

 cells called " fadeuzellen." A long, slender process, starting 

 from each of the " fadenzellen," is attached to the lip of the 

 funnel. To quote from Boveri : '^ Jede Zelle lauft namlich 

 in einen feinen, aber deutlich doppelt contourirten Faden 

 aus, der mit den iibrigen Auslaufern der gleichen Zellengruppe 

 zu einem Trichter hinzieht und in der Miindung desselben 

 eine Strecke weit verfolgt werden kann ; '^ and further : 

 '' Die Faden ziehen frei durch die Leibeshohle schrag 

 abwarts in die Trichteroffnung hinein gegen die laterale 

 Wand des Camilchens und heften sich mit ihnen Enden au 

 die Zellen des Nierenepithels an" (2). 



Some years ago, being struck with the resemblance these 

 ''fadenzellen" bear to the solenocytes I had just dis- 

 covered in the nephridia of Polycha3te worms, I examined the 

 kidneys of Amphioxus, and came to the conclusion that the 

 similarity Wcis only superficial, and that Boveri's description 

 was essentially correct (5, Part III). This winter, however, 

 whilst occupying the British Association table at the Stazione 

 Zoologica in Naples, I determined to re-examine these 

 organs, and I am now able to definitely state that the 

 "fadenzellen" of Amphioxus are indeed solenocytes of 

 typical, though somewhat peculiar structure (7). 



