AGASSIZ AND WOODWORTH : VARIATIONS IN EUCOPE. 141 
In a specimen with only three radial canals, one of which forks above 
the genitals, the formula is 
TE 
2, 15, 6, 7; 3, 10,1; 9, 2; 2, 5, 5; 
the otoliths being normal in number, but irregular in their distribution. 
In another Eucope with three radial canals, we find seven otoliths 
represented in the formula 
1,115: B54 1.655 2, 86 7 
the last sector being somewhat larger than the others. 
In a specimen with three equally developed sectors with the formula of 
12, 14, 6; 6, 7, 10; 6, 7, 15; 
there are six otoliths, the normal number in each sector, but the other 
marginal tentacles are most irregularly developed. 
In still another Eucope, similar to the preceding one, with three 
sectors of equal size and well developed genitals with six otoliths, two 
in each sector, the formula was 
10, 7, 10; 10, 9, 7; 9, 7, 8; 
Finally, a Eucope with three quadrants of the same size had only 
three otoliths ; its formula is 
Yi, 213.6 
The formation of spurs ee VIII. Figs. 4-13) takes place usually 
at the base of the marginal tentaele, at its connection with the circular 
canal, but cases have been observed in which the spur shoots off from 
the lash of the tentacle (Plate VIII. Fig. 5). The formation of spurs 
is often accompanied by the atrophy of the inframarginal knob of the 
marginal tentacles (compare Plate VIII. Figs. 9-13, with Figs. 4-8). 
It will be noticed that in the numerical variation of the segments the 
tendency is not to doubling the number of normal (4) segments, but 
either to add one or two, or to reduce the segments to three. 
In Sarsia, Agassiz observed a specimen with six radial canals and 
Romanes one with five; he also observed a Sarsia with six radial canals, 
six ocelli, and six wi like that seen by Agassiz, the only speci- 
men in thousands examined. 
According to Bateson, the numerical variations in Aurelia tend in two 
directions, i. e. to forms with six and twelve segments instead of the 
normal echte 
The same tendeney in Aurelia to vary in the direetion of six and 
