126 PROCEEDINGS OF THE ACADEMY OF [1889. 



di. digestive region of mesen- 

 terial filament. *//. lower sphincter. 

 £b.=Ectoderm. £.=tentacle. 



Plate VI. 



1. Transverse section through the middle region of the sphincter 

 of Aiptatia sp. (?) X 350. 



2. Longitudinal section through the upper half of the column 

 wall of Aiptasia sp. (?) X 40. 



'■). Transverse section through the outer edge of the longitudinal 

 mesenterial muscles of a specimen of Condylactis passiflora from the 

 Bermudas. X 42. 



4. Longitudinal section through the margin and adjacent parts 

 of Diplactis bermudensis. X 24. 



5. Longitudinal section through the margin and adjacent pails 

 of Oulactis fasciculaia. ;< 21. 



6. Transverse section through the longitudinal mesenterial mus- 

 cles below the stomatodseum in Diplactis bermudensis. X 40. 



Plate VII. 



1. Perfect mesentery of Diplactis bermudensis. Natural size. 



2. Portion of transverse section of sphincter of Diplactis ber- 

 mudensis. X 100. 



3. Transverse section of mesenterial filament of Zoanthus flos- 

 marinus just below the stomatodseum. X 120. 



4. Transverse section of perfect mesentery ofZoanth ug flos-marin us 

 slightly below the stoinatodseum. X 50. 



5. Mammillifera tuberculata. Natural size. 



6. One-fourth of a portion of a longitudinal section through the 

 column wall of M. tuberculata. X 200. 



7. Gemmaria Rusei. Natural size. 



8. Transverse section through the gonidial groove of Gemmaria 

 Rusei. X 65. 



9. Transverse section through upper part of column of Gemmaria 

 Rusei. X 24. 



