THE OXiCEPHALIDS. 



J. he Oxycephalids are perhaps the most interesting of all the Am- 

 phipoda Hyperiidea on account of their strange external forms as well 

 as the curious transformations which several of their internal and extern- 

 al organs are subjected to. However, it is not only because they pre- 

 sent such remarkable features as these that I have been induced to take 

 them up now. The many intricate questions connected with the syno- 

 nymy of the genera and species have to-day acquired an immediate inter- 

 est through the publication of two great works both of the highest im- 

 portance for our knowledge of the Amphipods, »Die Platysceliden» 

 by C. Claus in 1887, and »Report on the Amphipoda collected 

 by H. M. S. Challenger during the years 1873—1876», by the Rev. 

 Thomas R. R. Stebbing in 1888. As my own opinions with regard to the 

 synonymy and relationship of many of the Oxycephalidean species, briefly 

 stated in a preliminary paper »Systematical list of the Amphipoda 

 Hyperiidea», differ on several points from those of the eminent carci- 

 nologists just mentioned, I have felt in duty bound to state more fully 

 the reasons on which my systematical arrangement of this abnormal 

 group of animals is founded. Besides, I wish to make use of this op- 

 portunity for communicating some new results arrived at by the exami- 

 nation of fresh material recently obtained. 



As an introduction I am going to give some historical and mor- 

 phological notes on the Hyperids in question. 



Nova Acta Reg. Soc. Sc. Ups. 'Ser. I 



