1522 



A NATUBALIST IN CELEBES 



CH. VI 



flesh, do not project so far towards the centre. The lower 

 half of the diagram represents a transverse section of the 

 theca in the region of the dotted line zz', fig. 13. In this 

 region it may be noticed that the edges of the mesenteries 

 are free, so that there may be complete communication 

 between the intermesenterial chambers of the central por- 

 tion of the general cavity of the polype. At the edge of each 



-St, 



Fig. 14. — Diagram of transverse sections tlirougli a polype of Oalacea Esperi. 



The upper portion of the diagram represents a transverse section in the region indicated by 

 the dotted line x x' in fig. 13. The lower portion printed in dotted lines indicates a 

 transverse section in the region zz' in fig. 13. The reference letters are the same as 

 they are in fig. 13. 



mesentery there is a coiled thread, mf, the so-called me- 

 senterial filament, which plays an active and important 

 part in the processes of digestion. 



It is not my purpose in these pages to trouble the reader 

 with the species of corals that are found upon the reefs at 

 Talisse ; but I must refer just briefly to the most important 

 characters which separate the larger groups, in order that 



