136 NATURAL HISTORY OF OUR SHORES 



to have a dozen specimens perched on a branch of coralline 

 in a tumbler of water, and, unless they move, only a well- 

 trained eye will detect one. 



This species is set with curious little branched hairs, of 

 microscopic size, on different parts of the body, their position 

 very erratic, sometimes springing from an eye, from the tail, 

 the sides, or legs. It has been suggested that they are 

 sensory organs, also that they are due to a more complete 

 adaptation in the way of " mimicry," but no theory seems 

 to account at all well for them. 



Hippolyte cranchii. This is somewhat larger than the 

 last, very robust, with short, arched, and strongly serrated 

 rostrum. It is less frequently found than the others ; in 

 fact, it is considered a rare species. 



Hippolyte viridis (or Virbius viridis) is a slender form 

 about an inch and a half long, with a simple, sharp, and 

 prominent rostrum. When taken amongst sea -grass its 

 colour is always bright green, but when amongst fucus or 

 other dark weeds its colour is brown, so that its specific 

 name must not be considered as distinguishing. 



It no doubt has the colour adaptations of varians, but I 

 have not experimented on this one. 



The Crangonidce or " Shrimps " (all the smaller prawns, 

 as well as the Crangons, come under the name " Shrimp " 

 in the fish-markets) The familiar species is Crangon vulgaiis. 

 This abounds in all our sandy bays and estuaries. Its 

 form is " squat," and evenly tapered from head to tail. 

 The legs are shorter (more as in the insects) than those of 

 the prawns, and the rostrum, so conspicuous in the latter, 

 is represented by a little scalelike plate. 



Its colour is a minute speckling of -black on a buff or 

 whity brown ground, in imitation of the sand on which 

 it lives, and from which it seldom rises, for it has not the 

 swimming power of the prawns. 



I have taken specimens on a rocky part of the coast 



