38 



to siirrouuding objects, such as Laminaria, Delesseria, 

 Hydroids and Polyzoa. 



Eegeneration. 



Antedon has long been kuuwii to pustsess considerable 

 power of regeneration. The risceral mass may often be 

 detached with great ease, and, as shown by Dendy (9), may 

 be completely regenerated in the course of a few weeks. 

 Specimens are occasionally found (10) only partially evis- 

 cerated, and the original visceral mass remains, more or 

 less displaced, but Avith a new one developed in the normal 

 position. Przibram (11) found that the visceral mass could 

 be transplanted Avith success from one individual to 

 another. Regeneration and transplantation cannot occur, 

 however, in the absence of the apical nervous system. 

 Regeneration of the arms is of very frequent occurrence, 

 and not uncommonly results in monstrosity. Perrier (12) 

 has fully discussed regeneration of the arms. 



Parasites. 



Antedon bifida is the host of a number of parasites 

 and commensals, of which the best known are two species 

 of Myzostomidse, Myzustuma glahruni and M. cirriferum. 

 The former is found fixed in the neighbourhood of the 

 mouth in specimens from the Mediterranean and the 

 Adriatic, and the latter occurs in large numbers on the 

 disc and arms of specimens from the same localities as 

 well as from various parts of the British coasts, including 

 the Isle of Man. A small (iastropod, Stylina comatulicola, 

 is not uncommonly found attached by means of its pro- 

 boscis to the anal funnel or to the cirri of specimens from 

 the Mediterranean. Several Copepoda, including Collo- 

 cheres (jracilicauda, Brady, have been found attached to 



