PLATE I . 

 Struoturk op the Coral Skeleton. 



Fig. 1. Diagraniraatic representation of Mussa coialluni and soft parts, to show the relations between 

 hard and soft parts (after Ogilvie). The heavy black line represents the boundaries of the 

 flesh ; o., oral body-wall ; a., aboral body-wall ; e., edge zone (Randplatte) ; s., septum ; c, 

 costa; ps. th., psendotheoa ; i. s. 1., interseptal loeulus ; i. c. 1., intercostal loculus ; ep., ejii- 

 theca ; d., dissepiments, (lig. about natural size). 



Fig. 2. .Septnm o{ Manicina areoJata (L.). Section parallel to tlatsurfacc, X 5. l.d.,line of divergence 

 of the trabeculir ; tr., trabecuhc ; l.f., lineof fusion of trabecuhn ; ep., epitheca. 



Fig. 3. Cross section of septa and wall of Manicina areohitu (Linna'us), X 17. tr., trabeeuhi' ; ps. th., 

 pscndotheca ; d., dissepiment. 



Fig. 4. Section iiarallel to flat surface of septum of AiitiU'in ponderosa (Duncan). X 5. tr., trabecuhe. 



Fig. 5. Section parallel to flat surface of septum of 7?«smi;irt Itiorri Milne-Edwards and Haime, X 18. 



Fig. oa. Section parallel to flat surface of septum of EiiamiVta Inorri Milne-Edwards and Haime. Three 

 trabeculie magnified about 175 times. 

 Fig. 1, copy by Miss Frances Wieser; other drawings by Dr. J. C. McConnell. 



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