INTRODUCTION. XXXIX 



where there is usually no stolon, and the cells rise imme- 

 diately one from the other^ the connective cord is of 

 course not developed. But even amongst these there 

 are exceptions ; in Biceliaria ciliata, in which the true 

 zooecium is borne on a kind of peduncular support, the 

 latter is traversed by a cord, which communicates at the 

 base of the cell with the funiculus. 



In Memhrampora membranacea, each cell of which is 

 connected with several others, Nitsche describes two 

 lateral strings or funiculi, extending down the sides of 

 the zooecium, and in contact with each of the communi- 

 cation-plates, which occur at intervals in its walls *. 



But whatever may be the diversities of plan, the 

 endosarc is essentially one in histological character. It 

 remains to determine its function and physiological im- 

 port. 



Fritz Miiller was the first to attempt the interpretation 

 of this element of structure f ; and his views have been 

 widely accepted by subsequent writers on the Polyzoa. 

 He regards the funicular system as a true nervous struc- 

 ture, but one which is related to the life of the colony 

 rather than to that of the individual zooids composing it. 

 To him it is a common or colonial nervous system, which 

 has to do with " the associated movements " of the Poly- 

 zoa, or such as do not seem " to depend upon the will of the 

 individuals, but to be carried out by them in obedience, 

 as it were, to a command from a higher quarter." 

 Miiller's attention seems to have been first drawn to the 

 subject by the behaviour of the polypides in certain 

 cases, which appeared to point to the existence of a 



* Zeitsch. f. wissensch. Zool. xxi. Heft 4, p. 45. 



t Archiv fiir Natui-geschichte, 1860, p. 310, pi. xiii. ; translated in Quart. 

 Journ. Mier. Sc. vol. i. (n. s.) p. 300. 



