126 BULLETIN: MUSEUM OF COMPARATIVE ZOÖLOGY. 
genitals are fully developed, and equally so on each radial canal, of 
which there are four. 
The next stage represented by the formula, 1; 15; 1; 0 ; the genitals 
were atrophied on one of the radial canals and equally developed on 
the others. Seventy-eight specimens of this stage, 49 females and 29 
males. 
The next most frequent stage is that in which two adjoining genitals 
are fully developed ; the others are of the same size, but less well de- 
veloped ; that stage is represented by the formula 1; 1; 2; 2; Out of 
the 1,146 specimens examined there were only 74 specimens of this 
stage, of which 45 were females and 29 males. 
Next comes the stage in which only one of the genitals is fully de- 
yeloped ; the others are less so, corresponding to the formula 152; 2; 2; 
39 females and 27 males. 
In the order of frequency of occurrence comes : 
Eucope with the formula 1; 1; 1; 2; — 28 females and 17 males. 
Then comes the stage in which the genitals were unequally developed : 
20 females and 21 males. 
Next, 
Eucope with the formula 1; 0; 0; 0; — 24 females and 13 males. 
“ “ [T 1;2; 0; 0; — 15 “ « 3 « 
[73 [T 40 PARITI 0; — 10 [73 “ 8 66 
In specimens with three radial canals we observed only one specimen 
in which the genitals were uniformly developed. On Plate III. are seen 
(Fig. 1) a specimen in which one of the canals forks at the extremities of 
the heart-shaped genitals, forming three primary segments of nearly 
equal size extending to the centre of the disk, with a small sector cut 
from the outer edge of two adjoining segments. 
Figure 4 of the same plate shows a specimen with three radial canals 
and four genital pouches, but the canal which forks subdivides above 
the genitals so near the centre of the disk as to subdivide the disk into 
four nearly equal segments. 
A variation similar to that of Plate III. Fig. 1, for a three-rayed 
Eucope, has been observed in a four-rayed Eucope (Plate III. Fig. 2), in 
which the fifth sector is a comparatively small triangle cut out from the 
periphery of two of the adjoining sections, extending to the centre of 
the disk. 
In Figure 5 of Plate III. the forking of the four-rayed Eucope, taking 
place nearer the centre of the disk, subdivides the disk into segments of 
more uniform size, and it closely resembles a five-rayed Eucope. 
