MUSEUM OF COMPARATIVE ZOOLOGY, sl 
It might be difficult to determine whether in this group we have to do 
with dichotomy, did not the tips of the margins at times reveal the fact 
that there is no division of the ancestral series, but that a new one is 
added at the side of an ancestral one (Plate VIII. Fig. 69), where of 
the marginal individuals 4 is clearly median (ancestral) and 3 is lateral, 
13 median and 12 lateral, etc. (see page 49). 
The members of the group of Cyclostomata seem to be closely related, 
and the method of budding is so similar throughout the group that it 
seems fair to interpret the more compact Tubuliporide from the Crisiadee, 
In Crista, as we have seen, individuals are placed in rows, from which at 
intervals lateral rows are given off to the right or left. One may say 
that typically these are given off from each individual to both the right 
and the left, although in some cases, as in Figure 65°, lateral branches 
are typically given off alternately to the right and left, and are often 
aborted. Perhaps the most general formula of all for Cyclostomes should 
be that of two lateral branches from each individual, one or both of 
which may remain undeveloped. Such a formula I believe to be also 
the typical one for Bugula and its allies, and for the Alustrina and 
Escharina. It would be written thus:— 
* 
CH 
+» (*) * 
IRo (Doe 
* * * 
* Db * 
* x (x) * * 
# * (*) * *Beaaa* Be 
*a* eave. ii * * * * 
* * * 
(18) 3 D (*) C (*) B (x) A 
* * * 
* a* *aaar* * * * * 
* # (*) * * B (*)a a a(*) B * 
* * (*) x * 
wbs 
* * * 
ta ba* 
* (x) * 
* 8: % 
* 
in which the parenthesized asterisks indicate the presence of regenera- 
tive tissue. This is identical with (12) änd similar to (1). 
Braem (’90, pp. 130-133) has already called attention to the differ- 
ence between Phylactolamata and Gymnolemata in the orientation of the 
VOL. XXII. — NO. 1. 6 
