XV111 



INTRODUCTION. 



I have made similar observations on Plumularia setacea 

 and P. frutescens. On a young specimen of the latter 

 species obtained at Oban the nematophores were in a state 



Fig. vi. 



a 



Fig. vii. 



The calycle of Aglaophenia 



pluma. a. The lateral 

 nematophore. b. The ex- 

 tensile process. 



of great activity, sending out long filamentary processes, 

 which tended some upwards and some downwards, follow- 

 ing the course of the stem and branches, and completely 

 investing the zoophyte with a multitude of gossamer-like 

 threads. (Woodcut, fig. vii.) 



It has been conjectured that the nematophores are 

 organs of offence. But this is hardly probable, as they 

 only contain thread- cells in some cases, and when present 



layers ; but the ectoderm is of the simplest homogeneous texture a struc- 

 tureless contractile substance, not, unlike " sarcode " in any essential parti- 

 cular ; and the soft masses contained in the nematophores seem to be 

 ectodermal offshoots, somewhat less consolidated than the layer from which 

 they originate. 



