138 BULLETIN: MUSEUM OF COMPARATIVE ZOÖLOGY. 
ap np Number of 
Irregular, W Led 
74 0908 409 iy Bae Saw lean 20, Be S963 6 5, 1 forking. 
9/0/55 265 Oils ST s 3 3 
0p 5»007, To Dis DAD: 2, 01 0, 0,0 8 5 
7 O25 (5, S: 940:.147 5 5 4 
2, 8, 8; 3, 1, 3, 4; 1,8,2; 2, 8, 4; 9 4 
6, 6,7; 6,15; 6, 2; 1, 8, 63 6 4 
On Plate IX. will be found a number of diagrammatic figures giving 
an idea of the irregular growth of the marginal tentacles. The lengths 
of the tentacles are drawn as fully expanded, the position of the radial 
and circular canals is indicated, and the otolith tentacles are marked by 
a cross. The structure and length of the marginal tentacles of Eucope 
are such that the comparative length of adjoining tentacles is readily 
observed, owing to the slight degree of contraction and expansion they 
possess. 
In Figures 1 to 6, 10, and 14 (Plate IX.), we have the normal num- 
ber of tentacles (seven) in each of the primary quadrantie subdivisions. 
It is noticeable that /, can only in the case of Figures 4 and 10 be dis- 
tinguished from the two ½, while the four t, are of nearly uniform size 
in all the figures except Figure 6. 
In Figures 7, 12, 13, 16, 17 (one primary division), 18, 19, and 22— 
26, there are only five marginal tentacles in each primary quadrantic 
division. In the greater number of these figures it is possible to dis- 
tinguish ¢,, or f, and , while the irregularly developed tentacles are 
part of the 1, cycle. In Figures 20-22 (one sector) and 27-29 (two 
sectors), the cycles ¢, and t, can be distinguished, and the irregular- 
ity of development occurs in the t, cycle, which may appear at different 
points of the circular canal, as is seen by comparing Figures 20-22, 27, 
and 28. 
Figures 8-10, 17, 22, 29, and 30 show the irregularity in time of the 
development of the marginal tentacles in the different sectors of the same 
quadrant, as well as the irregularity in the growth of the three cycles 
^4-t, in adjoining sectors. In Figures 8, 29, and 30, the marginal 
tentacles between the otoliths are in the same stage of growth, but 
the tentacles of the right or left sectors are in very different stages of 
growth. In one case (Fig. 30) only one £, is developed in each sector; 
in Figure 29 the cycles of 4 and t are normal, while they are most 
irregular in the sectors of Figure 8. 
When six marginal tentacles occur in one seetor the irregularities in 
