PLATE III. . 



Figs. 28 — 32. Halimeda gracilis. 



Fig. 28. Forma typica. (Ceylon. Harvey, n°. 72). Nat. size. 



Fig. 29. Forma laxa. (Funafuti, type of H. laxa Bart.). 1 j s nat. size. 



Fig. 30. Filaments of central strand, shewing mode of fusion. 65. 



Fig. 31. Peripheral cells, surface view. > 140. 



Fig. 32. Peripheral cells, longitudinal view. 140. 



Figs. 33 — 38. Halimeda macroloba. 



Fig. 

 Fig. 

 Fig. 



Fig. 

 Fig. 

 Fig. 

 Fig. 



33. Habit of plant. (Botta, Arabia. Decaisne specimen in Herb. Mus. Paris). Nat. size. 



34. Filaments of central strand in longitudinal view, shewing pits at point of fusion. >< 140. 



35. Optical transverse section through apex of plant, just below the ends of the fused 



filaments ; shewing half of the central strand, the irregular outline of which is 

 clearly seen. The external walls of the outer filaments form one continuous layer, 

 which sharply delimits the strand. At :i: a few peripheral cells are shewn. < 140. 

 36^. One of the inner filaments from Fig. 35. x 365. 



36^. Longitudinal view of two filaments, similar to that of 36^. 



37. Peripheral cells, surface view. < 140. 



38. Peripheral cells, longitudinal view. >< 140. 



S65- 



