24 



GUIDE TO THE CORAL GALLERY. 



High Cases Class 11. SILICEA (^sUex, flint). Skeleton siliceous, horny, or 



I.-YI. and absent. 



Table Cases 

 1 and 2 a, b. 



Fis. 4 



A. Clathrina hianca X 20. b. The same x 80 (partly diagrammafic). rt.oscule; 

 6, pores; c, spicules ; f?, portion of wall turned back. c. Transverse section 

 of sponge (diagrammatic). D. A tiiree-rayed spicule X 300 diameters. 

 K. Collar cells x 1,200 diameters. (After E. A. Minchin.) 



Note. — In Fig. B, the spicules ought not to have been drawn close up to the 

 margin of the oscule ; also the figure is too broad and the pores far too large. 



Sub-Class [. Hexactinellida (/^e^-, six ; «Ms,ray). Six-Ray or 

 Glass Sponges. Siliceous spicules typically with three axes and six rays. 



