VoL. 2 | Robertson.—Non-Incrusting Bryozoa. 263 
a foothold. It seems to be almost the most abundant. bryozoan 
of the region; also found at many points in the vicinity of San 
Pedro. Less abundant northward, being found only in small 
quantities in San Francisco Bay and not obtained north of this 
locality. 
Caberea Lamouroux. 
Caberea Lamouroux, 1816. 
Flustra, (part), Johnston, 1847. 
Cellularia (part), Johnston, 1847. 
Caberea, Busk, 1852. 
Canda, d’Orbigny, 1850. 
Caberea, Smitt, 1867. 
Caberea, Hincks, 1880. 
Zoarium not articulated. Zoacia in two or more series, sub- 
quadrangular, or ovate, with a very large aperture. Sessile, 
frontal avicularia on the side and front of zocecia; lateral avicu- 
laria minute. Vibracular cells very large, placed in two rows, 
stretching obliquely downwards across the back of the zocecia, 
which they almost cover, to the median lne, notched above and 
traversed through a great portion of their length by a shallow 
groove. Vibracula usually toothed on one side. 
This genus is easily distinguished from others of this family 
by the peculiar shape and size of the vibracular cell as shown 
in fig. 46. It is not common in our collections, being repre- 
sented by only a small part of a colony of one species. 
14. Caberea ellisi Fleming. 
Pl. VIII, fig. 40; Pl. IX, figs. 45, 46. 
Flustra ellisii Fleming, Mem. Wern. Soe. ii, p. 251, Pl. 17, figs. 1-3. 
Flustra setacea Johnston, 1847, ed. Il, p. 346. 
Cellularia hookeri, Busk, 1852, pt. I, p. 37, Pl. XX XVIII, fig. 2. 
Caberea ellisii, Smitt, 1867, pp. 287 and 327, Pl. XVII, figs. 55, 56. 
Caberea ellisii, Hincks, 1880, p. 59, Pl. VIII, figs. 6-8. 
Zoarium fan-shaped, dichotomously branched ; branches thick, 
widening upward (Pl. VIII, fig. 40). Zowcia in two or four rows, 
short, subquadrangular (Pl. IX, fig. 45); aperture elliptical, 
occupying nearly the whole of the front, with a broad minutely 
eranular margin, sloping outwards; marginal zocecia with two 
stout spines above on the outer side, and one on the inner; 
intermediate zocecia with one spine on each side. Lateral avicu- 
