Howe : Phycological studies 103 



m 



i8. A sporangium-base, similar to that shown in Figure 17, in lateral view. 



19. A coronal process with seven hairs (including rudiments and scars). 



20. A rare form of coronal process with only five hairs (including rudiments and 

 scars). 



Figure 16 is drawn from no. jj/o (Atwood Cay, Bahamas) ; 17 and 18 from rio. 

 J7Jfa (Castle Island, Bahamas) ; 19 and 20 from no, jjis (Atwood Cay, Bahamas). 

 All of the figures are drawn from decalcified material and are enlarged 150 diameters. 



21. Acetabtdum polyphysoides delioideum 



Coronal -process, decalcified, viewed from above, and showing seven hairs (includ- 

 ing rudiments and scars). Drawn from the type material (Atwood Cay, Bahamas, 



Horve ^7ii\ and enlarfred iCo diameters_ 



Plate 7 



r 



I -4. Acetabulum ptaiUtim 



1. A mature plant, with lime coating. 



2, A mature fertile plant, decalcified. 



3, A large sterile plant, decalcified. (See Plate 6, Figures 13 and 14.) 



4, A large fertile disc with unusually obtuse sporangia, decalcified. (See Plate 6, 

 Figure 15). 



Figures 1-3 are drawn from the type material (Montego Bay, Jamaica, Howe 

 502ga) ; 4, from no, 54^3 (Mariguana, Bahamas). All of the figures are enlarged 16 

 diameters. 



+ 



5—9. Acetabulum polyphysoides 



5. A disc, decalcified, from above, showing twenty -five lightly coherent, obtusely 

 taper-pointed or subrostrate sporangia. (See Plate 6, Figures 17 and 18.) 



6. Sporangia from another disc, natural, the shaded areas indicating the distribu- 

 tion of the lime. 



7» A disc, decalcified, with seventeen free obtuse sporangia, showing also the cor- 

 rugated upper portion of the stipe. 



8. Sporangia, natural, the shaded areas indicating the extent and distribution of 



the calcification, 



9. More inflated sporangia, decalcified. (See Plate 6, Figure 16.) 



Figures 5-7 are drawn from no. 3731a (Castle Island, Bahamas) ; 8, from no, 

 502gb (Montego Bay, Jamaica) ; 9, from no. jjio (Atwood Cay, Bahamas). All of 

 the figures are enlarged 16 diameters. 



10. Acetabulum polyphysoides deltoideum 



A sterile disc, with seven sporangia, decalcified, from above. (See Plate 6, Fig- 

 ure 21.) Drawn from the type material (Atwood Cay, Bahamas, Howe 33 11) and 

 enlarged 16 diameters. 



Plate 8 



1-7. Udotea spinulosa 

 r. Cross-section of the flabellum, natural. The shading indicates rather too much 



lime for the medullary portions. 



2. Cross-section of the flabellum, decalcified. 



3. The tip of a filament from the apical margin of the flabellum, decalcified. 



4. Portion of a superficial filament from near the middle of the flabellum, decalci- 

 fied. The teeth form a part of the surface-covering of the flabellum 



