( 



Museums of England and Holland. 59 



tion that, in accordance with the law of correlation, the 

 number of columns in the electrical organs would also be 

 remarkably large. 



It merits my most grateful acknowledgments that Dr. 

 Gunther acceded to my pressing request and allowed me to 

 make the necessary anatomical examination of the typical 

 specimen — an examination which established the correctness 

 of the supposition expressed, and showed the three above- 

 mentioned species (T. occidentalism californica, and hebetans), 

 by the structure of their electrical organs also, to be three 

 nearly allied species. Now it will only be necessary to carry 

 out the numeration of the columns in T. nobiliana, Bon., 

 which has always been a doubtful species, in order to establish 

 its relations to the others. 



The above-indicated comparison satisfactorily confirms the 

 agreement of the marine faunas of the Atlantic and Pacific 

 coasts, already affirmed by Dr. Gunther himself upon other 

 investigations, as well as the diffusion of American forms of 

 marine animals as far as the European shores. 



Besides this particularly important result, I had now to 

 ascertain the structure of the electrical organs, their proportion 

 in the two sides of the body, and the mosaic of the columns, 

 from the material in the museum, in a series of rare or else- 

 where inaccessible species. These investigations were carried 

 out upon the following species, the greater part of which were 

 new to me, and most probably had never been previously ex- 

 amined for their electric organs — namely, Hypnos subniqrum, 

 A. Dum., Narcine tasmaniensis (adult and embryo), Narcine 

 lingula, Narcine Timlet, Torpedo fuscomacidata , Astrape di~ 

 pterygia, and Astrape capensis. Sketches were made for the 

 purpose of future comparison of the organs when exposed, as 

 well as of their relation to the form of the body ; the number 

 of columns was ascertained in all ; and the diagrams of the 

 numerations made with copying-ink upon glass were trans- 

 ferred to paper. 



Except Torpedo nobiliana (which I have never been able 

 to get hold of, in spite of all my endeavours) , no species now 

 exists in European museums which is not represented in the 

 tables compiled by me ; and for this gratifying completion I 

 am mainly indebted to the kind reception I met with in the 

 British Museum*. 



By constant hard work I was able to complete the above- 

 mentioned researches in the course of a week, and then went 

 to the Royal College of Surgeons, to ascertain whether any 



I do not know whether T. Tschudii exists in European collections. 



