PLATE VI. 



Spirastrella purpurea (Lmk.) Rdl. 

 Anatomy. 



Fig. I. S. E. 1945. Portion of the section from PI. V, fig. 9; X 50. 



Fig. 2. id. Three mastichorions in communication with in- and excurrent canals (2 and e); highly 



magnified (Zeiss, oil-imm. Oc. 4). 

 Fig. 3. id. Cells with large vacuoles; Zeiss, oil-imm. Oc. 4. 



Fig. 4. id. Scleroblasts; id. 



Fig. 5. S. E. 948b. Longitudinal section through one upper portion of a process (one side), showing the 



arrangement of canals and spicules ; a lumen of central canal (cf. PI. V, fig. 12, a); 



b peripheral canal (cf. PI. V, fig. 12, b)\ c rugae in section (cf. PI. V, figs. 1 and 4); 



d strings of fibroblasts; X 20. 

 Fig. 6. id. Portion of a transverse section through a process (cf. PI. V, fig. 13); a central; 



b peripheral canals; c ruga; d fibroblasts; x (cf. fig. 7); X 20. 

 Portion of fig. 6; the canal marked x corresponds to that in fig. 6; y (cf. fig. 8); X 100. 

 Portion of fig. 7 ; the canal marked y corresponds to that in fig. 7 ; t. sections of 



tylostyles; ;• 500 

 Portion of the tissue surrounding the central canal [a in fig. 20, PI. V). The concentric 



muscle cells are partly contracted and the membrane consequently stretched. The 



meshes between the flat cells have their long axes perpendicular on the canal-axis. 



Fig. 10. S. E. 948 b. Cells from the parenchyma; amoebocytes (?) ; haemat. eosine ; < 500. 

 Fig. 11. S. E. 948b. Cells from the parenchyma; Heidenhain ; •' 500. 



Fig. 12. S. E. 948b. Cells from the parenchyma, situated in fusiform strings (figs. 5 and 6d); transverse 



section ; Heidenhain ; X 500. 



