SIIIZOPOD.^. 51 



All these parts, he observes, become lummous on being 

 touched — renderhig the fingers luminous, " and if this 

 humour be scraped oflf with a knife and put into a glass 

 filled witli (fresh) water or milk and stirred with the finger 

 or a spatula, both those fluids will become phosphoric, wliicli 

 they will not when the moisture expressed from any other 

 part of the medusa is mixed with them" Travels, vol. IV. 

 p. 242-248. Query — Is the luminosity in the viscid 

 excretion, or in the animalculi which adhere to it^ and 

 which probably constitute the food of the animal ? 



Of Some Neto Genera of Luminous Crustacea, 



If we sometimes and at particular seasons witness the 

 sparkling appearance of the sea in the Temperate Zones, 

 within the limits of the Tropics it may be said to prevail 

 all the year round, and that in a remarkable degree, soon 

 after the sun dips beneath the horizon and that the light 

 of the moon is withdrawn. The individuals of the first of the 

 following Genera constitute a principal cause of this lumino- 

 sity, to which the others also contribute,— not that this 

 phenomenon, in the situation indicated, results solely from 

 luminous Crustacea, for a vast number and variety of 

 Mollusca, &c. have been ascertained to lend their aid 

 towards it. Although the muslin towing net cannot be 

 used with eff'ect in detecting these minute animals when 

 the progress of a vessel is considerable, yet we can often 

 succeed in capturing a luminous point now and then, by 

 suspending it by means of a very short line over the stern 

 in such manner as that it may just trip along the surface 

 or dip a little into the water on the heave of the sea, 

 taking care to hawl it quickly up when any of them appear 

 to be intercepted by it, and removing them with a camel-hair 

 pencil, into a glass vessel filled with sea water for exami- 

 nation the following morning : if the observer is either 



