my material bj' Giaid and Bonnier (the genus Clypconiscits G. andB.). Those authors had 

 just previously described an Epicarid living as a parasite on Ampelisca diadema Costa. 

 What I had found on Idotheid;* tempted me to go on looking for Epicaridea, so I examined 

 our Ampeliscidae and found — not these foi-ms, — but several species of Choniostomatidse 

 as well as another most remarkable parasite, wliich I described in 1892 under the name of 

 ItMzorUnaAmpelisc(e'S..S.'R. Professor Sars has told me (1886) that he had found some 

 species of Sphceronella on Ampliipoda. Now, as my own discoveries had called forth my 

 interest, I began in the Copenhagen Museum an examination of the material of Ampliipoda 

 and later on of the other orders of Malacostraca. 



Professor G. 0. Sars lent me all his material of this family for my researches, and 

 he further provided me with newly discovered forms — seven in all, — of which four are 

 particularly interesting; two of the most remarkable genera, the parasites on Mysidae, are 

 owing entirely to him — for all of wliich I have great pleasure in offering the eminent 

 naturalist my best thanks. — The Rev. Canon A. M. Norman, F. R. S. , lent me the types 

 of Aspidoecia Normani Giard and Bonnier, and the Rev. Th. R. R. Stebbing, F. R. S., 

 determined for me some Amphipoda from the Mediterranean, the West-Indies, the Cape and 

 Hong-Kong, for which I beg these gentlemen to accept my thanks. 



Last, not least, I wish to express my warm gi-atitude to the managing Committee 

 of the Carlsberg Fund for having allowed me a considerable sum to defray the expenses of 

 the present work. 



The English translation from the Danish manuscript is the work of Miss Louise 

 von Cossel. 



