124 BULLETIN: MUSEUM OF COMPARATIVE ZOÖLOGY. 
have become characteristic of jellyfishes, and result from their mode of 
life and the simplicity of their structure. Their repetition in closely 
allied genera may denote structural affinity, while in distantly allied 
groups it may be the result of mechanical combinations, and in no way 
indicate any affinity. 
The four primary segments of Eucope are of uniform size in the ma- 
jority of the specimens examined. Whenever there is suppression of a 
radial canal, as in the case of specimens with three radial canals, the 
segments are sometimes uniform (Plate III. Figs. 3, 6), or one of the 
segments, as in Plate III. Fig. 1, is nearly 180°, indicating the total sup- 
pression of the fourth radial canal at its normal point of development. 
See also Plate III. Fig. 4, in which one of the segments is smaller than 
the two from which the fourth section has been cut. 
The inequalities which exist in the segments of some of the Specimens 
can best be expressed by a table : — 
2 3. 3 6. 2.5 
I3 13 li-ii l; 1;—1; 3 lur. 1; 1 mE. 
5 5 3 4 4 2 83 18 
1; 15; 1; e gs Ui r 111-1; 1 113 Pp 11 
— 
2 3 3 3 er 
1515151111 11 PPL 1s 1; 1; 1; 
— — — 
1. 25, 25 25 1 26 35 86 36. 1 864 4 35 
F lee Leeds Ly ener eA 
5 2 2 
1315151 poh ah 1; T. 
The —-—. indicates a fork of the radial canal. 
see E5491 T EE 
1, m 1197; P AUTT TN a 1 1 1 15 
In this table 1 expresses the smallest segment; the approximate 
dimensions of the others are represented by multiples of it thus: x indi- 
cates that a segment is twice as wide at the periphery as the smallest ; 
= that it is three and a half times as wide. Of course, the value of 1 
is a different value in each case. 
