218 CRUSTACEA OF THE CHANNEL ISLANDS. 



rapidity, and when the environment is reversed, viz., from ^een to red, 



the chan'^c takes place more slowly, but still pretty quickly. And these 

 colours are not merely apioroxiniative, as in the Chameleon, so as to be 

 described as reddish or greenish, but most decided and vivid. The theory 

 has usually been that the change is brought about by the effect of the 

 surroundings on the optic nerve, and thence to those that control the 

 pigment supply ; but the experiments of Mv. Hornell, i)ublished in the 

 Journal of Micro-studies in Marine Zoology, show that light is not a 

 necessary factor in the change ; for red specimens placed among green 

 surroundings at night, and shut up in a cupboard, changed to bright 

 green all the same. Then, to my own surprise, during some experiments 

 I was making only a few weeks ago, deep chocolate specimens placed in a 

 white bowl, with no otherwise coloui'ed surroundings at all, became a 

 brilliant green in the course of two hours. One point more on this subject 

 of coloration. It is not a forcing to the surface of one kind of pigment, 

 so as to leave the other kind behind it, for if red and green specimens are 

 put into glass tubes in sea water, and examined with a magnifier b}' 

 transmitted light, it will be seen that the colour, be it red or green, is 

 uniform throughout the body, with the exception of a thin line, hardly 

 visible, of red, round the edge of the plates on the antennae and the telson. 

 This sj)ecies is abundant among corallines in all rocky pools from near 

 high water line to the lowest zone. 



Hippolyte Cranehii, Leach, a fine, robust little species. Not uncommon 

 with the last. 



Hippolyte faseigera, Gosse. Very much like H. varians but smaller, and 

 the colouring peculiar, closely resembling the purplish -brown nodular 

 twigs of the branching corallines among which it lives. I have not 

 noticed colour changes in this species. 



Hippolyte Viridis, Otto. A beautiful large Hippolyte common on our 

 shores, especially among Zostera, is, I think, the H. viridis of some 

 authorities, the Caradina viridis and Virbius viridia of others. Anung 

 Zostera it is green, among Fucus brown. 



Hippolyte Thompsoni, JBell. Frequent in Guernsey in 10 to 15 fathoms 

 (Rev. A. M. Norman). I have not seen living specimens. 



Pandalus annulieornis. Leach. Scarce in the Channel Islands, although 

 common on the British coasts, and often sold as the Prawn. 



Dennisia Sagfittifera, Norman. An exceedingly beautiful prawn -like crus- 

 tacean, about 1\ inches long, coloured as follows : — Hyaline ; on the third 

 and fourth somite of the abdomen saddle-shaped shields of rich pink, and 

 of terra -cotta- like surface, each saddle with a narrow border of creamy 

 white. The edges of the carap ice, limbs, squames of the antennae, and 

 edges of each somite, tail fins, and swimmerets bordered by a line of 

 small dots alternately purple and lemon yellow. The first specimen was 

 taken by Canon A. M. Norman in 1851 at St. Catherine's Bay, Jersey. 

 The second, as far as I am aware, was taken by myself in 1890 in St. 

 Clement's Bay, Jersey. The specimen from which I have taken the above 

 description was captured by Mr. Frank Wright near St. Peter-Port, 

 Guernsey, while dredging in 1905, and was handed to me alive. It is 

 still in my possession for transfer to the Guernsey JMuseum. 



Lysmata setieaudata, Risso. About the year 1889 I found a fine specimen 

 in a lobster-pot at La Rocque. Jersey ; and it was identified for me by 

 Canon Norman. It is a Mediterranean species, and I believe this is the 

 only record of its occurrence in these waters. 



Palsemon serratUS, Fabr. Common Prawn. Common, and largely fished 

 for the market. Taken by handnet within tide limit, and also in fairly 

 deep water by means of baited wicker traps called " prawn pots." 



Palsemon squilla, Fabr. Common. In the nomenclature of the fish 

 vendors, this species is the " shrimp," the last named species only being 

 distinguished as the " prawn." 



