282 University of California Publications. [| ZooLocy 
others short, showing a kind of alternation sometimes, and grow- 
ing decidedly shorter toward the distal end: zoccial origin of 
stalk segment not always apparent, and transition into ordinary 
zocecia, abrupt. Single stalks broad at point of attachment to 
substratum, sending out ribs (Pl. XIV, fig. 77, rb.) of chitinous 
material which are connected by a flat web-like disk of cuticle. 
In older stalks, branching occurs a short distance above the base. 
Colonies solitary, no instance found of runners or stolon-like 
processes uniting several. Zowcia resembling those of Bugula, 
especially of B. pacifica; elongated, only slightly narrower below 
than above; aperture occupying nearly the whole of the front; 
zocecia not turned outward nor is the aperture upturned (PI. 
XIV, fig. 80). Lateral margins of aperture raised, especially at 
the summit of the zocecia where each angle terminates in a long 
jointed spine; from the distal margin of a zocecium a second 
longer spine (sp.) appears, making two, less frequently three, on 
the outer margin, and one on the inner. Avicularia (av.) small, 
often minute, pedunculate, on the lower part of each zoccium 
just below the aperture. Oacia (oe.) globose, pedunculate, on 
the inner side at the summit of each zoecium. fRootlets spring- 
ing from lower segments of the branches of the stalk, passing 
downward close to stalk and attaching themselves to basal disk. 
(Pl. XIII, fig. 75, r.) | 
But two species of Stirparia have been hitherto described, S. 
glabra, Hineks (’83), and S. annulata, Maplestone (’79), both 
from Australian waters. To these, three others from the collec- 
tions on this coast are here added. In the three West American 
species, two types of zocecia are discernible, and two types of stalk 
segments. In all accounts hitherto given of this genus the Bicel- 
larian form of the zocecium is considered characteristic, so much 
so that Busk (’84) retains 8S. glabra in the genus Bicellaria. In 
the three species here described, there is shown a transition from 
the Bicellarian type to the Bugulan. Thus, S. ciliata closely 
resembles Bicellaria ciliata in shape and ornamentation of zoce- 
cium, but in S. occidentalis there is a decided approach to the 
Bugulan type, and in VS. californica we find the boat-shaped 
zocecium characteristic of Bugula. In all, the avicularia and 
