PLATE IT. 



Structure of the Gorai. Skeleton: Grai'iiularia pi'.rplexa. 



Fig. 1. Cross section of two sept:i of Siderastrea sji. (aftiT Ogilvic) ; syn., true syuaiiticiila; ps. syii., 



liseudosyuapticiila; cc, synapticular coalescence of sejita. 

 Fi(i. 2. Cross section of septa and wall of liiismUia Iciiorri Milne-Edwards and Ilaime, x 18, to sliow 



pseudotlipca. 

 Fig. 3. Crtiss section of septa and wall of i'ariiophtjUia curntiformis, to sliow psiiedotlieca, x 19- 

 FlG. 4. Cross section of septa and wall of Cdri/opliyllia comniiiiiix, to show eutUeca, X about 24. 

 Fig. 5. Cross section of septa and wall of Oculina diffusa Lamarck, to show eutbeca, X 17. 

 Fig. 6. Cross section of two se)>ta of Tliystiniis excciitiicits Duncan, x 18. Dissepiment shows lino of 



fusion between the two parts. 

 Figs. 7, 7a. 7b, 8, 8a., 8b, draphnlaria perpJexa (de Gregorio) (after d(^ Gregorio). The smaller fignres, 



7 and 8, natural size. (See p. 56.) 

 Fig. 1, cojiy by Miss Frances Wleser; other drawings by Dr. J. C. McCounell. 



212 



