PLATE XIII. 



LETTERING ON THE FIGURES. 



col. w., column -wall. 



c. is., cell-islet. 



c. s., ciliated streak (Flimmerstreif). 



cu. , cuticle. 



d., directives. 



disc, disc. 



ect., ectoderm. 



ect. can., .... ectodermal canal. 



ect. m., .... ectodermal muscle layer. 



enc. s., encircling sinus. 



end., endoderm. 



end. m., .... endodermal muscle layer. 



fb. L, fibrillar layer. 



fos., fossa. 



gl. c, gland cell. 



g. gr. gonidial groove. 



g. s., glandular streak 



(Driisenstreif , Nesseldriisenstreif ) . 



inc., incrustations. 



i. s., intermediate streak. 



lac, lacunae. 



m., .... . mesentery. 



m. fil. mesenterial filament. 



mes., mesogloea. 



mg. st marginal stoma. 



mr. m., .... maerocnemic mesentery. 



nem., nematoeyst. 



nr.l., nerve layer. 



oh. rn., oblique muscle. 



p. b. m., .... parieto-basilar muscle. 



per. st., . . . . perioral stoma. 



r. ect., reflected ectoderm. 



r. m., retractor muscle. 



r. s., reticular streak. 



s. d., sulcar directives. 



si. d., sulcular directives. 



sp., spermarium. 



sph. m., . . . . sphincter muscle. 



st., stoniodaeum. 



tent., tentacle. 



zoox., zooxanthellse. 



i., ii., in., &c, . . orders of mesenteries or tentacles 



Fig 



1. Bicordea florida. Transverse section towards the free edge of a mesentery a little below the 



stomodffial region, showing the imperfect mesenterial filament, x 250. 



2. Actinoporus elegans. Transverse section through a portion of the column-wall and of a mesentery, 



in the upper region of the polyp, x 320. 



3. Corynactis myrcia. Eadial section through the infolded region of the column-wall, x 250. 



4. Corynactis myrcia. Transverse section through a portion of a polyp near the aboral termination 



of the stomodseum. The stomoda^al wall is folded backwardly and outwardly upon itself, so 

 that it is here cut through twice, and the enclosed endoderm is shown on the left side. The 

 stomodEeum first terminates opposite the pair of directives. As the mesenteries cease their 

 connexion they retain around their free edge a tissue like that of the stomodseal ectoderm 

 which passes insensibly into the mesenterial filaments, x 50. 



5. Corynactis myrcia. Transverse section through the stem of a tentacle showing the brush-like 



character of the fibrillas radiating from the mesoglceal folds, x 320. 



Slightly reduced. 



6. Actinoporus elegans. Radial section through the upper part of the polyp 



7. Parazoanthus tunicans. Radial section through the distal region of the column-wall 



x 75. 



8. Parazoanthus separatus. Vertical section through the base, x 250. 



9. Parazoanthus monostichus. Transverse section of a polyp through the elevated peristome and 



capitular region. The peripheral tissues are disorganized as a result of the presence of the 

 numerous circularly-arranged sponge spicules, x 75. 



[ 216 ] 



