34 SYDNEY J. HICKSOX AND F. H. GRAVELY. 



FIG. 16. Lampra parvula. Adult and smaller zooids (x 1). c.p., chitinous pellicle; f.sp., feltwork 

 of sponge-spicules and diatoms in which the basal ends of the zooids are embedded ; r/ph., gonophores. 

 FIG. 17. Corynidae, sp. B. (x 10). lie., hydrocanlus ; hrh.f., Lydrorhizal filaments ; hyd., hydrauth. 

 FIG. 18. Myriothela ? (x 2). hrh.f., hydrorhizal filaments ; t., tentacles. 

 FIG. 19. Sertularella spiralis. Part of a pinnule ( x 25). ac., acrocyst ; ect., ectodermal sheath around 



base of hydranth ; gth., gonotheca ; op., opercular flaps. 

 FIG. 20. Sertularella spiralis ( x 25). Part of main axis, showing method of branching ; br., branch ; 



Mh., hydrotheca ; m.a., main axis. 

 FIG. 21. Sertularella plectilis (x 15). gth., young gonotheca; hyd., hydranth; r. hth., reduplicated 



hydrotheca ; s. hth., simple hydrotheca. 

 FIG. 22. Dietyoc ladium fuscum ( x 10). hth., hydrotheca ; st., stolon helping to bind the colony together 



by anastomosing with another branch. 

 FIG. 23. Plumularia t/lacialis ? . Central axis and proximal part of hydrocladia ( X 20). ? gth., 



female gonotheca ; h'h., hydrothecae ; nph., nematophores ; /. ltd., hydrocladia-bearing tube of 



central axis ; t. sp., supporting tubes. 

 FIG. 24. Plumularia glatialis <J . Part of a hydrocladium (x 40). $ gth., male gonotheca; hyd., 



hydranth ; n. hcl., node of hydrocladium ; nph., nematophore ; up., sperm. 



PLATE IV. 



FIG. 25. Campanularia verticillata, var. gramlis ( x 2). he., hydrocaulus ; hrh., hydrorhiza ; hyd., 



hydranth ; s., sponge growing upon the hydrocaulus. 

 FIG. 26. Campanularia laevis (x 7). gth., gonotheca; he., hydrocaulus; hrh., hydrorhiza; hyd., 



hydranth. 



FIG. 27. Halecium arboreim , part of a hydrocladium (x 20). <L, dactylozooid ; hyd., hydranth; 

 n., node ; nph., nematophore ; p., perisarc. (The measurements given in the text are of some 

 particularly well-expanded nematophores that we discovered after this figure was drawn.) 

 FIG. 28. Halecium arboreum. " Coppinia " mass ( X 1). cp.m., "coppinia" mass ; h.c., hydrocaulus. 

 FIG. 29. Halecium arboreum. Part of "coppinia" mass (x 15). d., dactylozooid; gth., gonotheca; 



nph., nematophore. 



FIG. 30. Obelia geniculata ( X 3) . To show mode of branching. 

 FIG. 31. Lafoeina longitheca (x 50). d., dactylozooid; hyd., hydranth; op. , opercular flaps; 



p., perisarc of hydrorhiza. 



FIG. 32. Diagrammatic longitudinal section of a male gonophore of Perujonimus antarctkus (x 50). 



ect., outer and inner ectoderm of umbrella in contact ; ect. u. i., inner ectoderm of umbrella ; 



ect. M. o., outer ectoderm of umbrella ; end. m., endoderm of inanubrium ; end. r. c., endoderm rod 



representing the ring-canal ; ms. m., mesogloea of manubrium ; ms. I., mesogloeal lamella of 



umbrella ; sp., sperm maturing from within outwards, and completely filling the subumbrella cavity ; 



it is omitted in the figure at su. c., to give greater clearness to the different parts of the gouophore. 



FIG. 33. Diagrammatic longitudinal section of male blastostyle of Stylactis Jialecii ( x 50). c.p., collar 



of perisarc around base of zooid ; ms., mesoglcca ; nc., nemutocyst in the ectoderm ; t., tentacle 



(entirely ectodermal) ; other letters as in fig. 32. 



FIG. 34. Diagrammatic longitudinal section of male gonophore of Tubular ia hodysoni (x 50). 



Letters as in figs. 32 and 33. 



FIG. 35. Diagrammatic longitudinal section of female gonophore of Lampra parvula ( x 30). end. u., 

 endoderm of umbrella ; ov ., ovum lying amongst the other rounded and deeply staining cells of the 

 endocodon ; ov. rup., ovum rupturing the " umbrella " and protruding part of its substance through 

 to the exterior ; other letters as in figs. 32 and 33. 



