496 F. ERNEST WEISS. 



would be the fact that they had become closed off from the 

 remaining portion of the coelom. Yet even this I do not con- 

 sider quite settled, as the tubules in many instances seem very 

 imperfectly closed off at their lower end, but I could not satisfy 

 myself that this was not due to faulty preparation. Still there 

 seemed to be no definite nephridial funnel^ so that I must 

 await further proof to consider them as closed off from the 

 coelom. 



They are in this particular similar to the atrio-coelomic 

 funnels described by Professor Lankester, but that they are 

 homologous structures with these belonging to a series of 

 primitively equal dorsalward extensions of the atrium I am 

 not inclined to believe, as the excreting tubules I have just 

 described occur regularly in connection with the secondary 

 gill bars of the region in which the atrio-coelomic funnels have 

 their opening. If the excreting tubules are simply extensions 

 of the atrium, they must be looked upon as analogous to and 

 not homologous with the atrio-coelomic funnels. 



Before concluding I should like to express my thanks for 

 help and suggestions I received during ray work to my teacher. 

 Professor E. Ray Lankester, and to Dr. Paul Mayer and Dr. 

 Hugo Eisig, of the Zoological Station at Naples. 



April, 1S90. 



Memoirs referred to. 



1. Johannes Mullek. — " Ueber den Bau und die Lebenserscheinuiigen des 



Brancliiostoma lubricum, Costa, Ampliioxus lanceolatus, 

 Yarrell," ' Abbandluugeu der Konigl. Akad. der Wissenscbaften,' 

 Berlin, 1841. 



2. E. Ray Lankesteb. — "Some New Points in tbe Anatomy of Am- 



pbioxus lanceolatus," 'Quart. Journ. Micr. Sci.,' vol. xv, 1875. 



3. E. Ray Lankestek. — "Contributions to tbe Knowledge of Am pbioxus 



lanceolatus, Yarrell," ' Quart. Journ. Micr. Sci.,' vol. xxix, 1889. 



4. Anton Schneider. — 'Beitrage zur Anatomic und Entwickluug der 



Wirbeltbiere,' Berlin, 1879. 



