GASTEROPODA. 311 
Dredged by Mr. Dyes, in three fathoms water, at Port Discovery, 
Puget Sound. 
This animal swims by lateral flexions of the body, the foot being 
then folded; and when crawling it is able to flex its enormous head 
laterally with considerable force. 
Figure 404, lateral view of the animal; 404 a, ventral view; 404 3, 
part of the circle of oral cirrhi, enlarged. 
Several nudibranchiate Gasteropods were observed in the Oregon 
region, but none of them were figured or described in sufficient detail 
to furnish specific characters. ‘They are interesting, however, as 
showing the correspondence of the generic forms in the northern 
Pacific and northern Atlantic waters. 
One species of DenpRonotus was obtained in Puget Sound, with 
the tips of the branchial tufts white. 
A Gontoporis of large size was also found at the same place. 
A Doris with a thick coriaceous skin, and coarse, white tubercles, 
dark in the intervals, resembling the tip of the arm of an Arterias. 
An Ko is with a single row of branchial papillz near the margin of 
the foot, leaving the dorsal region entirely exposed. 
Both from Puget Sound also. 
Umpretta Inpica of authors. 
ANIMAL somewhat hexagonal, spreading far beyond the shell, the 
exposed portion covered with very prominent tubercles of different 
sizes, growing smaller towards the margin, cream-coloured, with 
olive shadings in the fissures, increasing towards the margin. Branchie 
laciniated and fimbriated, orange-coloured; upper tentacles tubular, 
truncated at tip, slit at the side, breadth one-third their length; eyes 
on large tubercles at their inner base. When the head is extended, a 
