VOL. 2] Robertson.—Non-Incrusting Bryozoa. 218 
the sides of the zocecia frequently terminating above in a minute 
denticle (d.) ; aperture occupying two-thirds of the front; below 
the terminal denticle a spine (sp.) sometimes occurs. Avicu- 
laria characteristic, occurring on the lower half of the zocecia, 
to the side of the aperture and either just below, or 
just above its basal margin; on the intermediate zocecia, below 
the aperture; on marginal zocecia, usually above the base of the 
aperture; marked by great relative length of beak (bk.) and by 
the distinct sharp curve at its extremity; mandible also curved 
so that at rest the ‘“‘jaws’’ do not approximate each other except 
at the tip of the mandible (man.). As is often the case in multi- 
serial species the appendages of the marginal rows are larger 
than are those on the intermediate ones. In this case the mar- 
ginal avicularia (av.) are often gigantic in comparison with the 
intermediate ones (av.’). Ow@cia (fig. 58, oe.) globose, large, 
marked by faint strie. Rootlets (fig. 56, r.) very abundant, 
more numerous in the lower part of the colony, arising from 
the dorsal side of the marginal zocecia. Those arising on zocecia 
in upper part of colony frequently attach themselves to adja- 
cent branches to one side or below. 
In habit of growth and general appearance this species re- 
sembles B. murrayana. The difference, however, in the size of 
the various units of the colony in the two species will be clearly 
seen in a comparison of figs. 57 and 58, Pl. XI, with fig. 48, Pl. X, 
drawn to the same seale. In B. curvirostrata the spines are 
small, weak, and few in number, while the large size of those of 
B. murrayana is one of its distinguishing features. The avicu- 
laria are also very different both in size and shape; both species 
possess the curved beak, but the greater relative length of the 
beak of B. curvirostrata and its curvature which prevents its 
complete approximation with the mandible, separate this species 
from B. murrayana. 
B. curvirostrata has not been obtained north of Pacific Grove, 
but is found in considerable abundance at various localities south 
of this point. It appears to be characteristic of southern waters, 
and may perhaps occupy the place in the southern fauna taken 
in the north by B. murrayana. 
