VoL. 2 | Robertson.—Non-Incrusting Bryozoa. 275 
23. Bugula laxa, sp. nov. 
Pl. XII, figs. 61, 62. 
Zoarium consisting of numerous fronds much divided into 
segments possessing from two to fifteen rows of zoccia in a 
series (fig 61). The fronds forming tangled masses due to the 
great number of rootlets which attach themselves to other fronds 
or to other objects with which they are growing. Zowcia adher- 
ing very loosely together; narrowed below, having at each ante- 
rior angle a stiff prominent spine (fig. 62, st. sp.), and on each 
margin of the aperture a varying number of smaller spines 
(c. sp.) curving over and frequently meeting and overlapping 
in the middle line; the number of spines on a side varying from 
three or four, to six or nine, according to the position of the 
zocecium, the outer, marginal zocecia usually possessing, besides 
the stiff spines at the summit, nine spines at regular intervals 
along its length; the intermediate zocecia having a smaller num- 
ber; aperture occupying the whole of the front of the zocecium. 
Avicularia lacking. Oa@cia (oe.) rounded, prominent, with 
faintly radiating striw. Rootlets (fig. 62, r.) numerous, arising 
from the right or left dorsal anterior angle of the marginal, and 
of many of the intermediate zoccia. 
This species resembles both Bugula and Flustra so greatly 
that it is difficult to decide into which genus it should be placed. 
The shape of the zowcia, the looseness of their connection with 
each other, and more especially the fact that each individual 
zocecium arises from a bud formed independently from a parent 
zocecium, and not from a common growing marginal region as 
in the Flustras, indicate a closer relationship to Bugula. its 
habit is very characteristic. The great number of root fibres 
developed on its dorsal surface cause it to adhere somewhat 
closely to the substratum, in this case a sponge, and to form a 
tangled mass from which it is difficult to separate large pieces. 
The colony begins in a single zocecium from which either one 
or two buds arise forming branches which extend sometimes as 
long narrow strips of one or two series of zocecia, sometimes as 
broad fronds of many series. The adjacent rows of zocecia are 
