410 Abhandlungen der Koniglichen 



of Andromeda. Cephasa, and Medusa aurita in particular, numberless times in 

 his possession, and watched them both by day and night, but never once saw any 

 light issue from them. In July 1823, he observed near the shore at Moil eh, shoals 

 of Clupea erythrsea, which apparently emitted a brilliant light, but he supposes 

 that they only stirred up the water, and that the light proceeded in reality from 

 the before-mentioned luminous bodies with which it abounded. The oars caused 

 at intervals a similar appearance, which tended to confirm his opinion. 



During his stay in Arabia, Ehrenberg observed that as long as infusoria were 

 not removed from their native element, or from the substance to which they 

 were attached, they could be transported alive to a considerable distance. Thus 

 he carried a great number of them in a tin box, together with the conferva upon 

 which they were found, from Tor, on the Red Sea, three days journey towards 

 Mount Sinai, exposed to the burning heat of that climate, without their suffer- 

 ing any injury. As long as the confervse remained green, they retained their 

 vitality. Acting upon this knowledge, in 1830, he caused some bottles of sea 

 water to be sent from Kiel, on the East Sea, to Berlin, containing luminous mat- 

 ter, and found that, on shaking one of them, sparks were clearly visible. The 

 contents of another bottle failed to emit any. He then poured some of the wa- 

 ter from the former bottle into a glass, and dropped a little sulphuric acid into 

 it, when several bright flashes of light were seen. He found that the bottle con- 

 tained several species of living Cyclops, but that they were not luminous. He 

 also found a specimen of Synchaeta Baltica, which Michaelis had considered as 

 luminous, but it did not shew any signs of being so. The really luminous ani.. 

 mals were found at the bottom of the bottle. On taking one up in a drop of 

 water on the point of a pen, and adding a portion of sulphuric acid, it emitted 

 a spark, and died directly after. He arrived at the conclusion, that all the light 

 which was emitted ivoxn the Kiel water proceeded from many individuals of 

 one species, which he named Polynoe fulgurans, and of which he gives a highly 

 magnified representation. In 1832, he obtained more water from Kiel, when 

 these experiments were many times repeated, and always with the same success ; 

 by taking up a drop containing a specimen, and touching it with the acid, the 

 luminous properties of various new species were discovered. In no instance, 

 however, could he perceive any light issue from Synchaeta Baltica, and he ac- 

 counts for the variation between his own experiments, and those of Michaelis, 

 by supposing that the luminous properties depend upon the fruitful or unfruit- 

 ful state of the individual at the time. The specimens figured by Michaelis are 

 represented as carrying eggs with them, and as having a succession of them in the 

 ovarium. Those examined by Ehrenberg had the ovarium undeveloped. Not 

 one of the numerous Entomostraca, and especially the genus Cyclops, with which 

 the water was filled, and which greatly surpassed the other infusoria in size, 

 emitted any light. In 1833 the author was at Droebak, near Christiania, in Nor- 

 way, and obtained several species of luminous animals, and some new ones 

 amongst them, but none were infusoria. The light given out by Oceania mi- 

 croscopica is much clearer, brighter, and more white than the yellow sparks of 

 the infusoria. He was convinced that the light of Cydippe pileus proceeded 

 from the centre where the two ovaria are situated. In 1834 he tried several 

 experiments upon Medusa aurita at Wismar. The sea water in August ranged 

 from 11 to 4° Reaum. 



He placed specimens in spring water, in brandy, in sulphuric acid ; exposed 



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