8 NOCTILUCA MILIAIIIS. 



into foam by the revolving screw or paddles of the steamboat, 

 leaves in its wake a broad luminous track, as far as the eye can 

 reach. A glassful of water, taken from the surface of the sea at 

 such times, at once reveals the cause of this wonderful phe- 

 nomenon ; for here and there will be seen floating minute bladder- 

 like, transparent spheres. When irritated they at once respond by 

 flashes of green silvery lights, and it is to this that the beautiful 

 appearance already alluded to is due. 



This description is from the pen of Professor All man, who has 

 studied the Noctiluca very closely in its various stages, and I 

 venture to think he has under-rated rather than over-rated the 

 brilliancy of the phosphorescence. It was my good fortune on a 

 still moonlight night, last August, to be off the coast of North 

 Devon, and for some time to witness the appearance of molten 

 iron, which the paddles of the steamer caused as they churned up 

 the water, illumined on its surface by myriads of these tiny lamps. 

 The crests of the waves as they rippled against the shore were 

 sparkling with light, defining their form in sharp outline, and all 

 around the vessel the luminosity was most brilliant. The beauty 

 of the scene led me to commence these investigations, which I 

 have now the honour to place before the readers of this 

 journal. 



According to Suriray, Noctiluca Millaris consists of a 

 spherical, gelatinous mass, with a long filiform tentacle appendage, 

 possessing an oesophagus, many stomachs, and ramifying ovaries. 

 Huxley, however, describes the Noctiluca somewhat more 

 explicitly, by first stating that it is about the sixtieth part of an 

 inch in diameter, and next, that in appearance it closely resembles 

 a peach- — that is, one surface is a little excavated, whilst a groove 

 runs from one side of the excavation half way up to the other 

 pole. Where the stalk of the peach might be is a filiform tentacle 

 equal in length to about the diameter of the body, which exhibits 

 slow wavy motions when the creature is in full activity. The use 

 of this appears to be chiefly to push away obstacles and as a 

 motive power, and I venture to hazard the opinion that it is a 

 greater sympathetic nerve communicating with lesser nerves, and 

 thence to the luminous points at the apex of the body. If the 

 water is agitated in which the Noctiluca is confined, or an 



