Akademie tier Wissenschqften zu Berlin. 409 



as the occurrence of supernumerary bones, muscles, &c. This is done with a 

 view of establishing data for the analogy, or what may be called the philosophy 

 of the muscular system, which has hitherto been much neglected. Great praise 

 is due to the author of this valuable treatise for the diligence and accuracy dis- 

 played in his researches, and for the clearness with which the details are explain- 

 ed. The light which he has thrown upon the history of the Cyclostomous fishes 

 promises to be of great utility, and the scientific manner in which the inquiry is 

 conducted may serve as a model to future writers on comparative anatomy. 



Das Leutchen des Meeres. Von Herrn Ehrenberg This paper contains the 



result of numerous observations and experiments made by Ehrenberg upon ma- 

 rine luminous substances, between the years 1820 and 1834. Before entering 

 upon the subject, he gives an historical account of the notices of luminous phe- 

 nomena which are to be found scattered through the works of various authors, 

 from the days of Aristotle to the present time. The first detailed account of 

 marine light is given by Don Juan de Castro in 1541, in his Journal of a Voyage 

 in the Red Sea. Between that period and 1716, so many navigators had de- 

 scribed similar appearances, that in the latter year the Academy of Bordeaux of- 

 fered a prize for the best explanation of them, and the subject, so far from being 

 set at rest, still continues to excite curiosity. Ehrenberg mentions above 430 

 authors who have written upon the various kinds of light, both terrestrial and 

 marine, and has drawn up very interesting tables of the various substances, ani- 

 mal as well as vegetable, from which light has been emitted, according to all 

 these writers, forming a condensed history of the whole subject. 



The author's first observations were made in 1820, at Alexandria, in conjunc- 

 tion with Dr Hemprich. He there collected a quantity of luminous sea water, 

 which contained quantities of minute shapeless gelatinous bodies, which shone 

 like small sparks when the water was stirred. At Dongala on the Nile, in 

 1 822, he was much struck by the brilliant phosphorescence emitted from the 

 whole skeleton of Heterotis Nilotica, and which he never afterwards saw equal- 

 led in any other species either of fresh or salt water fish which he obtained, 

 though he thinks that the arsenical soap which he was obliged to apply in that 

 hot climate without delay, in the preparation of specimens, may have interfered 

 with it. Perhaps the Heterotis is the Dilychnos of Strabo which inhabited the 

 Nile, and whose eyes emitted a singularly brilliant light after death. The au- 

 thor remained stationary at Tor on the Red Sea, for five months, and was fre- 

 quently engaged in examining the sea water, which was found to be very full of 

 small slimy particles, without any determinate form, often having the edges jag- 

 ged, and which emitted light on stirring the water in which they were found. 

 They covered the marine plants, corals, &c. which consequently appeared lu- 

 minous ; every stroke of the oar caused them to sparkle, but he was never able to 

 detect any organization in them, and he never could satisfy himself that any of 

 the microscopic animals which he found with them in the water gave out light. 

 They did not unite and form large slimy masses, but were dispersed about in 

 small flakes. Decaying substances emitted no phosphoric light on the shores of 

 the Red Rea, probably owing to the rapidity of their decomposition. The larger 

 species of medusa are rarely met with. The Arabs call them all Kandil al 

 Bahr, or sea lanterns, and it seems that those medusa; which are generally ac- 

 counted luminous, only emit light at stated periods, as the author had specimens 



