VoL, 2] Robertson.—Non-Incrusting Bryozoa. 269 
the root fibres. More delicate in appearance than the preceding 
species, often tinted purple. Zowcia elongated, biserial, armed 
at the distal extremity with three spines, the outer one lone 
(300 »), projecting outward (Pl. X, fig. 50, sp.) ; the other two 
shorter (100 »), being continuations of the margin of the aper- 
ture (sp.’); Aperture occupying almost the whole of the front 
of the zoecium. Avicularia large, pedunculate, at the base and 
to the outer side of the aperture. Oq@cia remarkably small, not 
rising more than 60 or 80 » above the zoccium, while the em- 
bryo (emb.), in many cases measuring 200 p, extends down- 
ward into the upper part of the zoccium. Rootlets numerous. 
extending from the lowest zocecia of a colony. 
This species was formerly (’00) somewhat. tentatively iden- 
tified as B. purpurotincta Norman, but after more extended 
study of specimens from many different localities it is unques- 
tionably a new species. As formerly suggested by the writer, it 
is given the specific name pacifica, since it seems to be charac- 
teristic of the Pacific Coast. It ranges from Pribilof Islands, 
Bering Sea, to San Francisco Bay, the climax of growth. both 
in quantity and size being reached at Yakutat, Alaska. The 
purple color of the specimens obtained at this place is partic- 
ularly noticeable. This, as I have said, resides in part in the 
tissue lining the zoccia, and in part in the degenerated poly- 
* and is quickly lost after the material 
pides or ‘‘brown bodies,’ 
has been placed in alcohol. From one locality in Puget Sound 
where the species was obtained in abundance, it possessed a dis- 
tinctly greenish hue, while at many other places it is white or 
colored slightly yellow. The extreme shallowness and flatness 
of the omwcia are remarkable characters but are not peculiar 
to this species being found in at least one other species from 
this coast, Bugula longirostrata. The ovum matures in the 
upper part of the zocecium rather than in the occium, the em- 
bryo frequently blocking the mouth of the former. In all cases, 
where an embryo has formed, the polypide has degenerated into 
a ‘‘brown (purple) body.’’? Unlike those species which possess 
ocecia elevated above the mouth or orifice of the zowecium, func- 
tional polypides and embryos cannot exist simultaneously in 
