406 Dr. J. H. Pring's Observations and 



abdomen and sides, and which presented the appearance of as 

 many small stars spangling the surface of the skin. The 

 luminous gleam (which had sometimes an intermittent or 

 twinkling character, and at others shone steadily for several 

 minutes together) entirely disappeared after the death of the 



fish" It is almost needless to observe that there appears 

 little room for questioning a fact thus minutely and accurately 

 described. Another instance belonging to the Shark tribe, 

 (the Squalus fidgens) has also formed the subject of minute 

 investigation by the same observer. After describing the form 

 and structure of this fish, and noting accurately the portions 

 of the body devoted to the production of the light, he remarks, 

 " 1 am inclined to believe that the luminous power of this 

 shark resides in a peculiar secretion from the skin. It was 

 my first im})ression that the fish had accidentally contracted 

 some phosphorescent matter from the sea, or from the net in 

 which it was captured ; but the most rigid investigation did 

 not confirm this suspicion ; while the uniformity with which 

 the luminous gleam occupied certain portions of the body and 

 fins, its permanence during life, and decline and cessation 

 upon the approach and occurrence of death, did not leave a 

 doubt in my mind but that it was a vital principle, essential 

 to the oeconomy of the animal." 



Many of the Crustacea, of which the Cancer fulgens and the 

 Oniscus fulgens may serve as examples, are universally admit- 

 ted to be highly luminous. The Mollusca, both testaceous 

 and naked, afford well-marked instances of phosphorescence. 

 Amongst the former, examples of which are somewhat rare, 

 may be noticed the Cleodora cuspidatay described more par- 

 ticularly by Mr. Bennett, and also some of the Pholades, &c.; 

 whilst the latter contain the Salpee, the FyrosomatR, &c. 

 Amongst the Annelida we find the Nereides and the Polynoe 



J'ulgurans enjoying the same faculty; and the same may be 

 observed very generally of the Acalephae, the general phos- 

 phorescence of the ocean being chiefly due to the numerous 

 kinds of Medusae, Poly piferaB,Rotiferae, and Infusoria included 

 under this class, and more particularly in our own seas to the 

 microscopic example it contains, the Noctiluca miliaris, which 

 brings us to the special object of the present communication. ^ 



In noticing more particularly this minute yet powerful source 

 of oceanic light, I shall first give a brief account of the general 

 appearance imparted by its presence to the waters of our bay, 

 as exhibited for several successive nights during the months of 

 July and August last, and then describe more particularly the 

 little animal itself, and the various experiments to which it has 

 been subjected. 



