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SYDNEY J. HICKSON. 



pora, (4) an adelocodonic medusa, (5) the male gonophore of 

 Allopora, (6) the male gonophore of Distichopora, (7) the 

 female gonophore of Distichopora. 



Figs. 2 and 4 are copied from Allman with this modifica- 

 tion, that both endodermal tissue and endodermal cavity are 



Fig. 2. 



Fig. 3 



4. 



Fig. 7. 



Woodcuts 2 — 7. — The structure] of the different gonophores compared. 

 Diagrammatic sections of — 2. A phanerocodonic gonophore. 3. The me- 

 dusa of Millepora. 4. An adelocodonic gonophore. 5. Male gonophore 

 of AUopora. 6. Male gonophore of Distichopora. 7. Female gonophore 

 of Distichopora. A. Manubrium. B. Gonad. C. Endoderm. D. Ecto- 

 derm. E. Umbrella. 



represented in black. The diagrams are modified in this way, 

 because no important morphological distinctions can be drawn 

 between endodermal structures possessing a cavity and those 

 that do not. For example, no one would think of drawing a 



