MUSEUM OF COMPAEATIVE ZOOLOGY. 77 



EXPLANATION OF PLATES. 



PLATE L 



Figure 1. Eudendrium, sp. Remnant of a colony springing from a thickened fas- 

 cicled hydrorliiza. Natural size. 



" 2. Eudendrium, sp. The same species. Natural size. 



" 3. Obelia castellata, sp, nov. The entire specimen enlarged 10 times. 



" 4. 0. castellata, A portion of the trophosome. X 52. 



" 6. 0. castellata. A single hydrotheca in which occurred an uneven line in 

 the exact position for a floor or bottom. The hydrotheca is badly 

 wrinkled. X 52. 



" 6. 0. castellata. The entire specimen. Natural size. 



" 7. 0. castellata. A gonangium with its position on the stem. X 52. 



" 8. 0. castellata. Another gonangium in which there is a long wrinkle. 



X 52. 



PLATE II. 



Figure 9. 0. castellata. A gonangium. X 52. 



" 10. O. gelatinosa. A gonangium introduced for comparison. X 52. 



" 11. O. gelatinosa. A hydrotlieca, for comparison with those of 0. cos<e//ato. 



"x 52. 

 " 12. Ilalecium argenteum, sp. nov. Portion of a branch. X 52. 

 " 13. H. argenteum. Natural size. 



PLATE in. 



Figure 14. Lictorella genicidata, sp. nov. Part of a stem and branch. X 40. 

 " 15. L. geniculala. X 88. 

 " 16. L. genicidata. An entire colonj'. Natural size. 



PLATE IV. 



Figure 17. Sertularia variabilis, sp. nov. A colon}' with a compound stem. Natural 



size. 

 " 18. S. variabilis. A colony with a simple stem. Natural size. 

 " 19. S. variabilis. A single hydrotlieca. v, the valves ; o, the opening by 



which it communicates with the cavity of the stem; g, the aperture 



where the gonangium was attached. X 52. 

 " 20. S. variabilis. A portion of the trophosome with one gonangium. X 20. 



PLATE V. 

 Figures 21 and 22. Sertularia variabilis. X 20. 



