CORALLINES. 73 



vivacious, in fresh water, the pulp is expelled from 

 the tubes till they are almost emptied. 



But though the head falls soon after recovery 

 from the sea, according to sir J. G. Dalyell, it is 

 renewed at intervals of from ten days to several 

 weeks, but with the number of external organs 

 successively diminishing, though the stem is always 

 lengthened. It seems to rise within the tubular stem 

 from below, and to be dependent upon the internal 

 tenacious matter with which the tube is occupied. 

 A head springs from the remaining stem, very near 

 the root ; and a redundance of heads may be obtained 

 from artificial sections, as in the instance of the 

 hydra already described, apparently beyond the 

 ordinary provision of nature. Thus twenty-two 

 heads were produced in the course of five hundred 

 and fifty days, from the sections of a single stem. 



Johnstone says, of the coralline now presented, 

 " I have seen the antennae of a crab so pro- 

 fusely infested with this zoophyte as to resemble 

 hairy brushes. The creature had chosen, in this 

 instance, a station where it had all the advantages of 

 locomotion. This species is very minute. The 

 stem is a hair-like, horny tube, which creeps and 

 twists itself upon its support, throwing out at 

 alternate intervals a long slender twisted stalk, that 

 supports a bell-shaped cup of perfect transparency, 

 and prettily serrulated round the brim." 



The stems of another coralline* are clustered ; it 

 * Antenularia raraosa. 

 F 



