INTRODUCTION. 



XXXVll 



thin partition, present the appearance of a single sub- 

 globular collection of granules (Woodcut, fig. xv. ek). 

 The cord traversing one compartment is linked to that of 



Fig. XV. 



Ctenosfomatous stem. 



st. Stem. br. Branches, s. Septa, at the origin of the branches. 

 ec. Endosarcal cord. ek. Eudosarcal knot. 



the next by a thread-like extension of its substance, 

 which passes through the pore or pores in the septum. 

 Not unfrequently the cord gives off from its surface a 

 number of filamentary processes, which sometimes ana- 

 stomose, and sometimes pass directly to various points on 

 the wall of the tube, the whole forming a rude network 

 of fibres, or plexus. This portion of the structure is very 

 irregular and variable, and, according to Joliet's observa- 

 tions, is liable to frequent change and modification ^. 



* " Dans I'espace de peu de jours una portion du plexus s'est modifiee 

 sensiblement sous mes yeux, puisque j'ai vu un de ses rameaux s'atrophier 

 at disparaitre totalement." The foregoing account of the funicular sj-stem 

 is based chiefly on the researches of Joliet (' Bryozoaires des cotes de France ') 

 which I can confirm in most points from my own personal observation. 



