1880.] on Life in the Deep Sea. 333 



aro often useless to the animals possessing them as such, and may bo 

 merely accidental projiortics of cliemical compounds required for 

 otlier iiliysiolo^ical purposes. A large bottle full of a solution of the 

 bright red colouring matter of a deep-sea Pentacrinus was exhibited 

 to the audience, and the light was also thrown on the screen through 

 cells containing the solution. It is green when alkaline, red when 

 acid, and yields well-marked absorption-bands in the spectrum, which 

 were shown upon the screen. Other colouring matters of deep-sea 

 animals yield well-defined absorption spectra, and are hence easily 

 identified. In several instances the lecturer has proved them to be 

 identical with those of allied shallow-water or pelagic forms. 



The lecture was illustrated by numerous photographic figures 

 thrown upon the screen. 



[H. N. M.] 



