THE VICTORIAN NATURALIST. 99 



Amongst the Protozoa none is more highly phosphorescent 

 than Noctiluca, whose very name has been given on account of 

 this property. The organism is not spontaneously phosphores- 

 cent, but Professor Allman found that in certain definite spots in 

 the protoplasm the light comes and goes when the animal is 

 disturbed in any way. Another beautiful luminous protozoan is 

 ThalassicoUa, which is round in shape and somewhat larger 

 than Noctiluca. A section shows the intra and extra capsular 

 portions of the protoplasm, from the inner of which the light has 

 been seen to come. 



Most visitors to the seaside have seen phosphorescent zoo- 

 phytes, which somewhat resemble sea-weeds, on the shore, and 

 during my reading I came across an account of some exhibitions 

 of these zoophytes in 1841 by Hassall (15), which, I think, is 

 worth quoting. " Numerous friends can bear witness to the 

 extraordinary brilliancy of phosphorescent light emitted by a 

 great variety of species which I was in the habit of exliibiting to 

 them. Once each week I received from the master of a trawling 

 vessel on the Dublin coast a large hamper of zoophytes in a 

 recent state. In the evening these were taken to a dark room 

 and the spectators assembled. I then used to gather up with my 

 hands as much of the contents of the hamper as I could manage, 

 and tossing them about in all directions, thousands of little stars 

 shone out brightly from the obscurity, exhibiting a spectacle 

 which, to be appreciated, must be seen, and one which it has 

 been the lot of but few persons as yet to have looked upon." 



One of the most brilliantly phosphorescent of these forms is 

 Pennatula phosphorea, one of the sea-pens, or cock's comb, as it 

 is called. This is a colony consisting of numerous polypes 

 imbedded in a common mass. Each polyp has been shown to 

 possess eight luii inous bands round the short alimentary canal, 

 and when the colony is touched the light commences at the point 

 irritated, and gradually spreads in both directions over the whole. 



Among the polychaete worms, which for the most part live 

 along the sea-shore in rock crevices, or burrow in the sand 

 between tide marks. Professor Benham (6) singles out Chsetop- 

 terus, a European form, as the " most eminently photogenic." 

 The illustrations show the animal with its body curiously 

 modified in shape, and also the appearance in the dark on 

 stimulation. The body is almost entirely outlined by the light it 

 gives — the so-called wings, the fans, tentacles, and hinder portion 

 of the body are all so brilliantly lighted up that the light is quite 

 good enough to read one's watch by. Many other members of 

 this group are also phosphorescent — one of them, Polynoe, has 

 phosphorescent "wings," which it frequently throws off, appar- 

 ently to deceive its enemies. 



Amongst the mollusca, one in particular is interesting as 



