PROCEEDINGS 



ROYAL SOCIETY OF EDINBURGH. 



VOL. II. 1844-5. No. 25. 



Sixty-Second Session. 



Monday, 2d December 1844. 

 Sir T. M. BRISBANE, Bart., President, in the Chair. 



The following Communications were read : — 



1. Account of the late Earthquake atDemerara. By W. H. 



Campbell, Esq. Communicated by M. Ponton, Esq. 



2. On the Existence of an Electrical Apparatus in the Flapper 



Skate and other Rays. By James Stark, M.D., Fellow 

 of the Royal College of Physicians, Edinburgh. 



The author, after noticing the fishes in which an electrical ap- 

 paratus had been discovered, stated that, with the exception of 

 Geoffrey St Hilaire, no writer had endeavoured to shew that Skates 

 possessed electrical organs. The organ to which that writer al- 

 luded, the author regarded as nothing else than muciparous ducts, 

 identical with the very same organs in the Torpedo, and quite 

 distinct from the electrical organs. The circumstance was then 

 mentioned which directed the author's attention to the tail of the 

 skate, and led him to suppose that an electrical organ might exist in it. 



On removing the skin from the tail of a Flapper Skate, an organ 

 was discovered occupying the place of the lateral muscles, extend- 

 ing from near the base to the very tip of the tail, and possessing 

 all the anatomical characters of the electrical apparatus of fishes. It 

 was about 14 inches in length, and about half an inch in diameter for 

 nearly one-half of its length ; was composed of columns or four-sided 

 membranou.s tubes, about the twelfth of an incii in diameter, divided 



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