286 NATURAL HISTORY OF OUR SHORES 



convinced that it was millipore, while a transparent 

 hump might suggest something delectable. It is good 

 mimicry. 1 



An error which has become classical is in regard to 

 mysis. A large species of this has been named Mysis 

 chamceleon, on account of its being supposed to vary its 

 colour to suit surroundings, and this is often used as the 

 typical case of colour change. I cannot understand this, 

 except that it results from copying an original error. 



As a matter of fact no mysis (at least no mysis on this 

 shore) does change colour, nor has colour to change. They are 

 all pretty well transparent, just a line of grey, or faint greenish 

 grey spots of pigment along the back one spot on the 

 carapace and one oneach segment. These spots have narrow, 

 waved lines radiating from them. I have to-day been 

 watching a swarm of M. chamceleon in a Zostera pool. 

 They showed, when viewed from above, on a sandy bottom 

 of a grey colour, but were not conspicuous. They swam 

 slowly, and looked like the little bits of decayed Zostera, 

 which were common around. A few placed in a bottle of 

 water and viewed from the side showed the transparency 

 and the lines mentioned. 



It is with great hesitation that I make this objection to 

 the very general opinion especially when I consider the 

 names that have appeared in connection with it and again 

 say, on this coast, at least, the mysids do not show change 

 of colour, and mysis abounds here. I have already men- 

 tioned how it forms a law- regulated fishery. 



I cannot help thinking that the error is due to having 

 confounded mysis with the slender Hippolyte (or Virbius) 

 viridis. 



In the mollusca there is great variety of colour and 



1 Since the above has been in print, the Rev. A. M. Norman 

 has identified this specimen for me. It is Denicia sagittifera. 

 First recorded and named by him in 1851. 



