ESCHAIUDvE. 335 



for the outrageous gapings and eccentric jerks in which 

 they indulge. They occur on several British species, as, 

 for example, Flustra avicularis and Cellularia avicularis. 



" While watching, on one occasion, a piece of the latter 

 zoophyte through the microscope, a worm, passed over it 

 and among its branches. It was almost immediately firmly 

 grasped by one of the avicularia, and forcibly detained. 

 In a short time one end of it was seized by another, from 

 which, however, by its violent contortions, it extricated 

 itself, but not without injury. The first assailant, mean- 

 while, kept fast hold, and soon two others caught the un- 

 fortunate at different points of the body. Thus it was held 

 securely pinioned ; and all its efforts to disengage itself, 

 which were most vigorous, proved unavailing. The avicu- 

 laria grasped the body of their victim most viciously, and 

 nearly divided it. When I last observed the contest, the 

 worm seemed exhausted by its struggles, and scarcely 

 stirred; the beaks remaining firm and motionless. These 

 strange police-officers were very systematic in their opera- 

 tions, and, in capturing the intruder, seemed to be dis- 

 charging a very ordinary function. 



" There can be little doubt, I think, that it is the office 

 of these organs to defend the Bryozoon from its enemies. 



