30 



Balanoglossus Kowalevskii (Agassiz), fyc. [Dec. 18, 



tion of these points, together with a detailed account of the anatomy 

 and development, is reserved for a subsequent occasion. 



It may, nevertheless, be advisable to point out that since, according 

 to Spengel, the tissue of the " water vessel " of Tornaria forms the 

 lining of the proboscis cavity of B. minutus, this " water vessel " is 

 therefore the same structure as the anterior body cavity in the form 

 just described. If then the " water vessel " of Tornaria is comparable 

 to the "water vessel " of Bipinnaria, which has a similarly asymme- 

 trical development upon the left hand side of the body, which view 

 has been held by all previous observers, it would therefore appear to 

 follow that the water vessel of Bipinnaria is prima facie comparable 

 with the asymmetrical anterior body cavity of Amphioxus. 



List of Papers referred to. 



1. Agassiz, Alex., " Hist, of Balanoglossus and Tornaria," " Mem. 

 Amer. Acad.," vol. ix. 



2. Balfour, E. M., " Monograph on Elasmobranch Fishes," 1878. 



3. Bateson, W\, " Early Stages in dev. of Balanoglossus," " Quart. 

 Journ. Micr. Sci.," April, 1884. 



4. Hatschek, B., " Stud, iib Entw. d. Amphioxus," Claus' " Arbeiten," 

 Wien, 1881. 



5. Hatschek, B., "Mitth. iib. Amphioxus," " Zool. Anz.," Sept. 29, 

 1884. 



6. Kowalevsky, A., " Anatomie des Balanoglossus," "Mem. Acad. 

 Imp. Sci.," St. Petersburg, 1866. 



7. Metschnikoff,E., " Ueb. d. Metam. einiger. Seethiere," " Z. f. W. 

 Z ," 20, 1870. 



8. Lankester, E. Bay, " New Points in Structure of Amphioxus," 

 " Q. J. M. S.," xv, p. 257. 



9. Mefcschnikoff, E., " Ueb. d. Syst. Stell. v. Balanoglossus," "Zool. 

 Anz.," 1881. 



10. Scott, W. B., " Beitrage z. Entw. d. Petromyzonten," " Morph. 

 Jahrb.," Bd. vii. 



11. Spengel, J. W., " Bau. u. Entw. v. Balanoglossus," " Tag. d. 

 Naturf. Ver.," Munchen, 1877. 



12. Spengel, J. W., "Z. Anat. d. Balanoglossus," "Mitth. a d. 

 Zool. Sta. z. Neapel.," Bd. 5, Hft. iii and iv. 



