SYSTEMATICAL NOTES. 15 



These three subtribes correspond exactly with the three subdivi- 

 sions A, B, and C in 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 Hype"rines auormales)) of MILNE EDWARDS, the family 

 Typhidce of DANA, or the families Platyscelidce, Phorcidce and Oxycephalidce 

 together, of SPENCE BATE, and lastly the same limitation as the 

 scelidenj) of GLAUS. 



B. Characteristics for the distinction of the Families in the 

 subtribe HYPERIIDEA CURVICORNIA. 



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



2. The form of the seventh pair of perceopoda. 



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



4. The development of the mouth-organs. 



5. The second pair of perceopoda transformed, or not transformed. 



The first characteristic distinguishes the Parascelidce and Euhyphidce 

 from the remaining families. The second distinguishes the Phor cor aphides, 

 the Lycceidce, and the Oxycephalidce from the Pronoidce, Eutyphidce, and Xi- 

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

 tion of the genus Xiphocephalus. The third characteristic separates 

 the families Phorcoraphidce, Pronoidce, Euthamneidce, and Xiphocephalidce 

 from the families Lycceidce,- Oxycephalidce, Parascelidce, and Eutyphidce. 

 The fourth characteristic distinguishes the Lycceidce^ from the Oxyce- 

 phalidce and the Xiphocephalidce, and the Parascelidce from the Eutyphidce. 

 The fifth distinguishes the Phorcoraphidce from all the other families. 



Within the subtribe I place the family Phorcorhaphidce first because 

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

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

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

 Hyperiidean families with the Isopods, especially with the Sphseromids, 

 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. 



