PLATE XIII. 



LETTERING ON THE FIGURES. 



col. w column wall. 



c-is., cell-islet. 



"• « ciliated streak (Flimmerstreif). 



ctt cuticle. 



d; directives. 



disc, disc. 



««'., ectoderm. 



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



ect. m., .... ectodeiTaal muscle layer. 



tnc. s., encircling sinus. 



end., endoderm. 



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



/*• I., fibrillar layer. 



/os fossa. 



ffl- c., gland cell. 



ff- g^-1 gonidial grooTe. 



?■ '•> glandular streak 



( Driisenstreif , Nesseldriisenstreif ) . 



•"<^-> incrustations. 



»•■'■. intermediate streak. 



'"'^■j lacunse. 



m., .... . mesentery. 



m. fil. mesenterial filament. 



mes., mesogloea. 



mg. st marginal stoma. 



inr. ?«., .... macrocnemic mesentery. 



nem., uematocyst. 



«'■■ I., nerve layer. 



oJ. in., oblique muscle. 



p. i- «' parieto-basilar muscle. 



per. st perioral stoma. 



>'. ect., reflected ectoderm. 



r. in., retractor muscle. 



r. s., reticular streak. 



s. d., sulcar directives. 



si. d., sulcular directives. 



sp spermarium. 



sph. in., .... sphincter muscle. 



5^, stomodoeum. 



tent., tentacle. 



zoox zooxanthellEB. 



I., II., III., &c., . . orders of mesenteries or tentacles. 



Figure 

 1. 



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

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



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

 in the upper region of the polyp, x 320. 



Corynactis m.yrcia. Eadial section through the infolded region of the column-wall, x 250. 



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

 of the stomodasum. The stomodajal 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 

 stomodiEum 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 stomodteal ectoderm 

 which passes insensibly into the mesenterial filaments, x 50. 



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

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



Actinoporus elegans. Eadial section through the upper part of the polyp. Slightly reduced. 



Parazoanthus tunicans. Eadial section through the distal region of the column-wall, x 76. 



Parazoanthiis separatus. Vertical section through the base, x 250. 



Parazoanthiis 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. 



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