TEGUMENTARY ORGANS— SKIN STRUCTURES. 4 6 7 



they may well be treated under this head. Everywhere 

 the deposit is in the epidermis; for even the partitions 

 are infoldings of the epiderm. 



Fig. 326. — Simplified figure of an actinia. 



We recall, then, the structure of the soft polyp, with 

 its radiating partitions, and reproduce the figure show- 

 ing it (Fig. 326). Now, in corals, the structure is the 



1 jlll'J^f'/ljf! 



ii 11 li 1 1 iw'''W : /i ii L'li'i 



Fig. 327. — Ideal section, vertical and horizontal, showing structure : i, ten- 

 tacles ; s, stomach ; p p, partitions. 



same, except that deposits of lime carbonate are formed 

 in the lower part — i. e., in the foot disk, the walls, and 

 the partitions to more than midway up the animal, 

 but leaving the upper part of the wall, partitions, and 



