PLATE XV. 



LETTERING ON THE FIGURES. 



eol. IV., .... column wall. 



c. is cell-islet. 



c. s., ciUated streak (Flimmerstreif). 



cu., cuticle. 



d., directives. 



disc, disc. 



ect ectoderm. 



ecL can., .... ectodermal canal. 



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



ene. s., encircling sinus. 



end endoderm. 



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



//>. I., fibrillar layer. 



fos., fossa. 



gl. c, gland cell. 



g. gr., gonidial groove. 



g. s., glandular streak. 



(Driisenstreif , N esseldriisenstreif) . 



inc., incrustations. 



i. s., intermediate streak. 



lac lacunae. 



m. mesentery. 



m. fil. mesenterial filament. 



mes., mesogloea. 



mg. St., .... marginal stoma. 



mr. in., .... macrocnemic mesentery. 



nem., nematocyst. 



nr. I., nerve layer. 



ob. )«., oblique muscle. 



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



per. St., .... perioral stoma. 



r. ect., reflected ectoderm. 



r. m., retractor muscle. 



r. $., reticular streak. 



s. d., sulcar dii-ectives. 



si. d., sulcular directives. 



sp., spermarium. 



sph. in sphincter muscle. 



St stomodaeum. 



tent., tentacle. 



zoox., zooxanthellse. 



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



Figure 



1. Homostichanthus anemone. Transverse section through the knob of a tentacle. 



320. 



2. Actinoporus elegans. Radial section through the wall of the fossa and across the sphincter 



muscle. X 25. 



3. Corynactis myrcia. Transverse section through a mesentery a little below the stomodaeal region. 



The mesenterial filament at the free edge is simple, while the endoderm behind is swollen, 

 giving somewhat the appearance of a trilobed filament, x 320. 



4. Parazoanthus tunicans. Transverse section of a polyp through the lower part of the stomodseum. 



The lacunas represent the spaces from which the calcareous incrustations have been dissolved ; 

 the sponge spicules remain, x 50. 



5. Parazoanthus tunicans. Section through a fold of a mesentery containing three spermaria. x 320. 



[ 220 J 



