Systematical Notes. 15 



These three subtribes correspond exactly with the three subdivi- 

 sions A, B, and C iu the synoptical diagram given in my »Contributions 

 to a Monograph of the Amphipoda Hyperiidea», (p. 3) issued in 1887. The 

 first two subtribes have not the same limits as the first two subdivisions 

 proposed by Milne Edwards and Dana, but the third has almost the same 

 limitation as the »Hypérines anormales» of Milne Edwards, the family 

 Typhidœ of Dana, or the families Platyscel.idce, Phorcidce and Oxycephalidœ 

 together, of Spence Bate, and lastly the same limitation as the DPlaty- 

 scelideny> of Claus. 



B. Characteristics for the distinction of the Families in the 

 subtribe HYPERIIDEA CURVICORNIA. 



1. The form of the femur of the sixth pair of perœopoda. 



2. The form of the seventh jiair of perœopoda. 



3. The telson coalesced with the last ural segment, — or free. 



4. The development of the mouth-organs. 



5. The second, pair of perœopoda transformed, — or not transformed. 



The first cliaracteristic distinguishes the Parascelidœ and Euhyphidœ 

 from the remaining families. The second distinguishes the Phorcorajjhidœ., 

 the Lycœidœ, and the Oxycephalidœ from the Pronoidœ, Eutyjjhidœ, and Xi- 

 phocephalidœ., this last family being instituted here by me for the recep- 

 tion of the genus Xiphocephalus. The third characteristic separates 

 the families Phor cor aphid œ.^ Pronoidœ.^ Euthamneidœ., and Xiphocepiialidœ 

 from the families Lycaddce., Oxycephalidœ, Parascelidœ.^ and Eutypihidce. 

 The fourth characteristic distinguishes the Lycœidœ^) from the Oxyce- 

 phalidœ and the Xiphocephalidœ, and the Parascelidœ from the Eutyphidœ. 

 The fifth distinguishes the Phorcorajjhidœ from all the other families. 



Within the subtribe I place the family Phorcorhaphidœ first because 

 it comes nearest to the Hyperiidea filicornia owing to the situa- 

 tion of the first pair of antennœ ; last in the whole tribe I place the 

 family Eutyphidœ., because it seems to show the most affinity of any of the 

 Hyperiidean families with the Isopods, especially with the Sphaeromids, 

 owing to the form of the body and the very intimate coalition between 



1) As this characteristic is of no use in an external examination another but 

 less good characteristic is used in the synoptical table p. 18. 



