288 University of California Publications. [ ZooLocy 
irregular intervals; mandible triangular, pointing downward. 
Oawcia? Rootlets not very numerous, springing from the lower 
internodes of a colony. 
This is a handsome, well marked species, originally figured 
and described by Busk from the west Greenland shore. It is 
abundant on the rocks at Orea, Prinee Williams Sound. It 
seems to be a strictly northern species not being reported south 
of Queen Charlotte Islands. 
832. Cellaria mandibulata Hincks. 
Pl. XV, figs. 87, 88, 89; Pl. XVI, fig. 103. 
Cellaria mandibulata Hineks, 1882, p. 462. 
Cellaria mandibulata Hincks, 1884, p. 203, Pl. TX, fig. 7. 
Zoarium forming masses of delicate branches often growing 
from 75-90 mm. in height (Pl. XVI, fig. 103). Internodes 
slender. short, the longest from 6 to 8 mm. in length. Branch- 
ing irregular, branches usually arising near the top of an inter- 
node, but often from the middle, or from any point on its sur- 
face; when arising from the top of an internode, two branches 
are seldom opposite, the one usually being higher than the other. 
Joints black. Zoacia of various shapes depending apparently 
upon age. In young stages, they are slender, narrowed almost 
to a point above and below, widest about the middle (Pl. XV, 
fig. 87) ; in older stages they are somewhat wider, truncate above 
and below (fig. 88); in the oldest stage, zocecia broader and 
shorter relatively (fig. 89) ; alternate, in a line from one end of 
the internode to the other, surrounded by a broad more or less 
ecrenulate border (fig. 88, cr. bor.). In young stages, this border 
follows the length of the internode in sinuous lines which ap- 
proach each other but do not meet above and below the zoccia 
(fig. 87); in older stages, the sinuous border becomes united 
above and below the zocecia, and the crenulations are less marked 
(fig. 89). Zocecial wall convex, covered with minute punctures, 
which in the oldest stage seem to cover the border with one 
continuous slightly punctate mantle (fig. 89). Operculum (op.) 
semicircular, with straight lower margin, a denticle at each lower 
