INTRODUCTION 27 



an incomplete differentiation of reproductive and 

 vegetative cells in the plants which possess them. 

 It may be so, but the point is by no means 

 established. The special amyloplastic function of 

 the chromatophore, as distinguished from its 

 assimilative one, appears to be limited to that portion 

 immediately investing the pyrenoid. If the change of 

 size of the pyrenoids be associated with the nutritive 

 state of the cell, as appears probable, it would con- 

 firm the opinion that they are reserves of proteid. 



In collecting seaweeds between tide-marks the 

 nature of the appropriate equipment is so obvious 

 as to need little direction. The most convenient 

 receptacle for specimens is the ordinary waterproof 

 sponge-bag, though a tinned iron milk-can with a 

 good lid has its advantages. In no case should glass 

 bottles be carried in the hand or pocket, since they 

 are a source of danger, and unnecessary. For similar 

 reasons a knife is an undesirable companion in 

 slippery places, and it is not needed if the collector 

 carry a stout stick of the alpenstock pattern, with a 

 chisel screwed into one end for scraping off 

 specimens, and a small landing-net ring provided 

 with a cotton bag instead of a net attached to the 

 other end. The stick is useful for support, and the 

 bag for securing floating specimens that have been 

 detached by the chisel. Wading boots are of great 

 advantage, except where there are deep pools, when 

 the risk attending immersion is greatly increased by 

 their use. 



Though a storm is often more productive than a 

 dredging expedition, the specimens are frequently 



