314 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1924 



where the migratory instinct begins to assert itself the desire for 

 food, otherwise voracious, is lessened, the body takes on a metallic 

 sheen, and the pectorals become black and pointed. In this guise 

 the ells are termed " silver eels," their flesh is very firm and rich in 

 fat, and they are thus well equipped for entering upon their second 

 and last great journey, this time back to the breeding grounds 

 across the ocean. 



Before concluding this survey of the Danish eel investigations it 

 is my pleasurable duty to thank all those who have contributed to 

 the progress of the same. I have already mentioned how decisively 

 important was the aid afforded us from outside. Special thanks 

 are here due to Admiral H. R. H. Prince Valdemar, of Denmark, 

 and to His Excellency H. N. Andersen, director of the East Asiatic 

 Co., of Copenhagen. But in our Commission for Investigation of 

 the Sea also, much, and most valuable work has been done to further 

 these investigations first and foremost by the chairman. Commodore 

 C. F. Drechsel, Danish R. N. 



Last, but not least, I thank my assistants who helped to carry 

 out the actual work at sea and on land. These, during the first 

 years, A. Strubberg, M.Sc, later P. Jespersen, M.Sc, and A. V. 

 Taning, M.Sc, have each taken a great share of the work with 

 much skill and enthusiasm. Further, the captain of our research 

 vessel, Capt. G. Hansen, has, in addition to the other duties fall- 

 ing to his share, on more than one occasion carried out work on 

 board which called for training in marine biological research. 



POSTSCRIPT 



Do the Indo-Pacific fresh-water eels hreed in the sea like those of 

 the Atlantic, and do they, like these, undergo a larval development 

 ivith metamorphosis f 



The present work has up to now considered only the two Atlantic 

 species, the European and the American eel. 



There are, however, in the Indo-Pacific region also fresh-water 

 eels of the genus AnguUla, and, moreover, many more species than 

 in the Atlantic area. 



What is the life history of the Indo-Pacific eels ? 



Do these eels breed in the sea, like the two Atlantic forms; have 

 they similar larval stages; and do they, like those of the Atlantic, 

 undergo a retrograde metamorphosis from larva to elver? 



Nothing is Imown as to this. And even if we had larvae which 

 might be supposed to belong to one of the Indo-Pacific Anguilla 

 species, they could not be identified from what is generally known, 

 as the information afforded by extant literature as to classification of 

 the Indo-Pacific eels is insufficient. The limits of the different 



