14 CARL BOVALLIUS, THE OXYCEPHALIDS. 



characteristics used by DANA, only a relative quantity though it is true 

 that it is carried to the extreme point in the Eutyphidce. The third is a 

 good characteristic for distinguishing the Eutyphidce and the Scelidce from 

 the Oxycephalidce and the Phorcidce, but unhappily the Pronoidce, and some 

 forms of the Lycceidce are intermediate. The fourth is, in my opinion, 

 very uncertain and liable to sexual variation. The fifth is a valuable 

 characteristic for distinguishing the family Eutyphidce from the family Sce- 

 lidce, but it is difficult to use it in external examination. 



After a long study of the different forms of the Amphipoda Hy- 

 periidea I have arrived at the conviction that there are a number of char- 

 acteristics, little or not at all appreciated by previous authors, but useful 

 for the distinction of subtribes, families arid genera within the tribe 

 Amphipoda Hyperiidea, of them I quote. the most important here. 



A. Characteristics for the distinction of the Subtribes of the 

 AMPHIPODA HYPERIIDEA. 



1. The point of fixation of the first pair of antennce. 



2. The shape of the same pair of antennce. 



3. The number of joints of the flagellum of the same pair of antennae 



in the male. 



According to these characteristics I propose to divide the Hype- 

 rids into three subtribes: 



I. Hyperiidea recticornia. 



Diagn. The first pair of antennas are fixed at the anterior part 

 of the head, they are straight, the first joint of the flagellum is 

 large, the following few in number and terminal. 



II. Hyperiidea filicornia. 



Diagn. The first pair of antenna are fixed at the' anterior part 

 of the head, they are straight, the first joint of the flagellum is 

 large, the following many in number (c?), filiform and terminal. 



III. Hyperiidea curvicornia. 



Diagn. The first pair of antennae are fixed at the inferior part 

 of the head, they are curved (j 1 ), the first joint of the flagellum 

 is very large, the following few in number and subterminal 



