OUT OF THE DEPTHS 129 



such stations as Rothesay, Oban, and Glasgow. 

 There are also further points to be investigated, 

 such as the nature, extent, and origin of the 

 phosphorescence which is another characteristic 

 of all the creatures, and the reason why the 

 sea-pen is called Pennatula phosphorea. Is this 

 light electrical, or due to some spontaneously 

 inflammable substance? or is it due to special 

 phosphorescent organs, bands of fatty substance 

 " cordoni luminosi," as Panceri calls them in 

 his studies on the phosphorescence of marine 

 animals? Lastly, as Darwin says, "What is an 

 individual?" How suggestive is the fact that 

 these creatures are, from one point of view, the 

 homes of innumerable polyps, feeding indepen- 

 dently, and even capable of separate existence ; 

 while from another they are one creature re- 

 treating into the mud, in the instance of the 

 sea-rush, crawling and waving its feathers with 

 one motion, in that of the sea-pen ; even if its 

 swimming rapidly, or at all, is treated as dis- 

 proved ! If a colony, how obedient are its 

 subjects ! if a unit, how singularly independent 

 are its different parts ! 



But it is high time that we should return to 

 our dredging, and this time we pass across 

 nearly to the other side of the loch before we 

 let down our net for a draught. As we row 

 across, a seal puts up his round, shiny head 

 within fifty yards of the boat, and after a good 



I 



