VoL. 2 | Robertson.—Non-Incrusting Bryozoa. 261 
Perhaps the most striking feature of this species is the pecu- 
liar size and prominence of many of the lateral avicularia. This 
is brought about by the great extension of the beak and is not due 
to increase of the muscular portion (mus.) ; thus, in fig. 39 (¢. av.) 
the mandible (man.) is seen to be longer than the muscular 
part, and to be more than half as long as the whole appendage. 
In the shape of its vibracular chamber and in the unusually 
large size of its lateral avicularia, this species resembles S. cali- 
fornica, but as has been said, the increase of size of the avicularia 
in the two eases is due to increase of different parts of the organ. 
In other respects, S. varians and S. californica are very unlike, 
e.g., in habit, in shape of seuta, and more especially in abund- 
ance of the vibracular chambers and length of the vibracula. 
Although this species has been obtained in small quantities on 
the California coast as far south as San Pedro and La Jolla, it 
is characteristically a more northern form. It was first described 
by Hineks from Queen Charlotte Islands, and it is abundant 
in Puget Sound, both on Channel Rocks, and at San Juan. 
Material obtained in the south was dredged at 32 fathoms, while 
in Puget Sound this species is a shore form. 
13. Serupocellaria diegensis, sp. nov. 
Pl. IX, figs. 41, 42, 43, 44; Pl. XVI, fig. 96. 
Zoarium forming a coarse bushy mass often 50 mm. in 
height (Pl. XVI, fig. 96). Branching dichotomous, internodes 
consisting of a variable number of zocecia, nine. thirteen, 
seventeen or more, especially in the terminal internodes. Joints 
somewhat inconspicuous, often occurring as high on the zocecium 
as the lower margin of the aperture. Zoacia biserial, the two 
rows inclined at an angle so that the internode is keeled, and 
in cross section is triangular; rather short and broad, shghtly 
narrowed below (Pl. IX, fig. 41); aperture oval, with a wide 
margin, and occupying more than half the front surface. Scu- 
tum (sc.) in older zocecia large, covering more than half the 
aperture, thickened on the inner surface and raised on a ped- 
unele. Spines three, four, or five, the one immediately above 
the seutum, and frequently the one opposite, bifid (67. sp.). In 
