196 



SYDNEY J. HICKSON. 



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

 tion, that both endodermal tissue and endodermal cavity are 



Fig. 2 



Fig. 5. 



Fig. 3, 



F.c. 4. 



Fig. 6. 



Fig. 7 



Woodcuts 2 — 7. The structures of the dififerent gonophorcs compared. 

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

 Medusa of Millepora. 4. An adelocodonic gonophore. 5. Male gono- 

 phore of Allopora. 6. Male gonophore of Distichopora. 7. Female 

 gonophore of Distichopora. A. Manubrium. B. Gonad. C. Endoderm. 

 D. Ectoderm. 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 

 fine morphological distinction between the dactylozooids of 

 Millepora and those of Allopora because in the case of the 



