86 BULLETIN OF THE 
the phytoid stocks of Bugula, and in creeping corms like Lepralia or 
Cristatella, may be explained as affording additional strength on the one 
hand, and as a device for saving space on the other. 
The absence of true dichotomy, which I have sought to show charac- 
terizes the budding of Bryozoa, is interesting as seeming to indicate 
the fundamental similarity of the process of budding in Paludicella to 
that found elsewhere. The tip of the branch does not divide equally 
in the first nor in the other instances, but constantly maintains its 
precedence, giving off parts of itself to form lateral branches. These 
parts may grow out at right angles to the primary branch, as in Palu- 
dicella, but generally they grow forward nearly parallel to it, as in 
most marine Gymnolsemata. 
In Bugula (Plate VII. Fig. 64°) branches are always given off 
toward the axils, and therefore an ancestral branch gives off all lateral 
branches from one side and the successive orders of branches are given 
off alternately to the right and left. In Crisia, on the contrary, branches 
are given off abawially, and they are given off not from one side only, 
but alternately to the right and left. In both cases the two facts are 
mutually dependent. The first case gives rise to a stock in which the 
branching tends as greatly as possible towards compactness and the for- 
mation of a closely built stock ; the second case gives rise to a diffuse 
and loosely built stock (cf. Figs. 64, 65, and 64", 65"). In the sec- 
ond case there is a maximum space’ to each individual ; in the first, 
a maximum economy of space. 
The rule that lateral buds on two closely related branches tend to 
arise in the same generation is one that, as has been shown, is more 
or less apparent in some cases, but is easily obscured by other rules, 
May not the tendency be due to the same causes that produce the 
synchronism of division in related cells of a cleaving egg! 
That lateral buds should occur in Bugula flabellata on the outermost 
rows only is not surprising when we reflect that there is abundant room 
on the margin, whereas the inner individuals are hemmed in from lat- 
eral expansion by the pressure of adjacent rows. This is very marked in 
certain repent colonies, as, for instance, occasionally in Membranipora 
(Plate VIII. Fig. 70). Here the intermediate branches 6, 7, 8, and 9 
have produced no lateral buds for many generations, while almost every 
individual of the marginal rows has given rise to a lateral branch. It is 
merely a result of the same cause, it seems to me, that lateral budding 
occurs more frequently in Bugula turrita at the margins of fans than 
elsewhere. Here there is room to spread. 
