280 University of California Publications. [ ZOOLOGY 
becoming branched, and attaching themselves to grains of sand, 
to hydroid stems, or other substrata. 
In the possession of a chitinous stalk marked by constrictions 
more or less deep but not distinctly articulated, S. ciliata is re- 
lated to S. annulata, Maplestone (°79). It differs markedly from 
that species, however, in the total lack of the annulations found 
on the segments of the stalk of S. annulata and for which it is 
named. Many evidences are afforded of the zoccial origin of 
these segments. Instances are found where a segment assumes 
the shape externally of an ordinary zocecium, 7.e., it becomes 
wider at the distal end and possesses an aperture on whose mar- 
ein are two and sometimes three spines (Pl. XII, fig. 68, ab. ap.). 
The contents of such a segment, however, are similar to that of 
adjacent segments. The avicularia which are usually minute 
often become more numerous and slightly larger near the tips of 
the branches. 
This is a rather widely distributed California species, being 
found among the material from Lands End, Fort Point, and 
Lime Point, San Francisco Bay; Pacific Grove, Mendocino City, 
and Dillons Beach, California. 
27. Stirparia occidentalis, sp. nov. 
Pl. XIII; figs. 72, 73, 74. 
Zoarium composed of flabellate tufts borne on the summit of 
a number of erect, stiff, segmented branching stalks, the whole 
an inch or a little more in height (fig. 72). The segments (seg.) 
of the stalk not so evidently aborted zocecia as are those of the 
preceding species, the lateral aborted apertures appearing only 
occasionally; the articulation (art.) of the segments distinct ; 
segments differing in length, growing noticeably shorter to- 
ward the distal end of the stalk, and the transition (tr.) from 
stalk to zocwcial tuft being very sudden. Zocecial tufts relatively 
short, not half as long as the main stalk, branching dichotomous. 
Zoecia biserial, alternate; at the formation of a branch, the 
series of zocecia separated by the interpolation of two new zocecia 
on the inner side so that no one zocecium ean be said to be at 
