PLATE 26. 



Porpema prunella. 



Fig. 1. Radial section, from a photograph. Lettering as in fig. 2. X 11. 



Fig. 2. Reconstructed radial section. The left half is between two radial ridges of the centra- 

 denia, the right half in the plane of one of the ridges. 



Sti', primary; Sti', secondary stigmata, opening into the central chamber (Ch), and into 

 the circular chambers (Ch. C',Ch.C-); Li, linibus; Gl.Mu, mucous gland; C. Li, canals of 

 the limbus; C. T, radial canals of the tentacular zone; C. S, superior canals of the centra- 

 denia(Cd); Tr, trachea; Gz, central gastrozooid; Go, gonozooid; T, tentacle. X about 20. 

 Fig. 3. Apical view, showing radial rows of stigmata (Sti), pahal canals (C. Pa), and marginal 

 mucous glands (Gl. Mu). X about 20. 



Fig. 4. Transverse section of the pneumatophore close to the apex. Lettering as in fig. 2. From 

 a photograph. X 35. 



Fig. 5. Transverse section of corm just below the apex of the centradenia. Lettering as in fig. 2. 

 From a photograph. X 20. 



Fig. 6. Similar section at the mid-level of the centradenia. From a photograph. X 20. 

 Fig. 7. Longitudinal section of young tentacle. From a photograph. X 90. 



