SEA-FAN MAKERS. 201 



polyp is fixed. There is not, perhaps, in nature 

 a single law whose reverse is not also found in 

 operation. 



We find in these animals, just as we do in vege- 

 tables, stalks and branches covered with real bark ; 

 but the stems, or axes, of the animals are horny or 

 calcareous, while those of the vegetables are herba- 

 ceous and woody. In each case the tissue is more 

 or less solid, striated, or fluted, and formed of con- 

 centric layers ; and, moreover, the cortex of the coral 

 is spongy, and somewhat soft, like the bark of a 

 vegetable production. The knobs represent the 

 buds ; the polypes, the flowers ; 

 the feelers open themselves out 

 in rosettes as petals, forming an 

 animated corolla, which opens and 

 shuts alternately (fig. 39). In the 

 polypier, the individuals which 

 contribute to the growth of the 

 whole are situated at the ex- 

 tremities of the axis, or upon its 

 sides, a position similar to that of FIG. 39. 



the leaves and flowers in a plant. A RED CORAL POLYPE ' 

 And the final resemblance is found in their modes 

 of reproducing their species. The corals, and the 

 vegetables, are each produced by isolated and indi- 

 vidual grains, eggs, and seeds, which separate them- 

 selves from a bunch, and proceed to develop them- 



