448 E. B. Wilson—The early stages of Renilla. 
(a, a, of the last figure,) have now well-developed tentacles, and 
four new pairs of zooids have appeared. Of these the first to 
appear are the pair }, 6, behind the primary pair; they are fol- 
lowed by ¢, c, in front of the primary pair, and these by d, d, 
still farther forward. The fifth pair e, e, appear in the angle 
etween a, a, and 6, 6. Besides these, which all develop into 
sexual zooids, a pair of rudimentary zooids, 7’, 7’, have ap- 
peared, and also an odd one, 7’, which, however, has normally 
a fellow on the opposite side. 
The subsequent development consists in the growth of these 
sexual zooids, the constant development of uew ones in the 
angles between contiguous preéxisting sexual zooids, and the 
appearance of a series of rudimentary zooids on the upper side 
of each sexual zooid. And at length each rudimentary zooid, 
he mode of budding exhibited by the rudimentary zooids 
ony; so that each group 
tition of the whole colony. As might be expected, there is 
some irregularity in the multiplication of these zooids; and the 
following description applies to the most usual method as de- 
termined by the study of a large number of cases. 
Figure 5 gives an enlarged view of one of the simple zooids 
shown in fig. 4. The small median chamber (which may as 
before be called the lower chamber) is always turned approxi 
mately toward the center of the disc, that is, away from the 
oral extremity of the sexual zooid on which it is situated. 
