132 
PACIFIC SCIENCE, Vol. IX, April, 1955 
cles, which in Doris cardinalis are bilobed, but 
in the two species here described are multi- 
lobular. 
Hexabranchus aureomarginatus sp. nov. 
Fig. 15, PL 2 
Body much depressed, oval in outline when 
cloak is fully extended. Cloak wide and very 
thin at edges, serving as swimming lobes. A 
median dorsal area, corresponding to the body 
region, is bright red with groups of fine white 
flecks, some of which are concentrated to 
form large spots of irregular outline. Lateral 
to this area is one of pale rose, interrupted 
anteriorly, but continued posteriorly by a nar- 
row connection with a corresponding area of 
the opposite side. Marginal region consisting 
of three rather narrow uninterrupted color 
zones: innermost bright red; middle white 
with radially disposed muscle bands; outer- 
most golden yellow. Rhinophores long and 
stout, with about 40 golden laminae and with 
basal stems of reddish orange with a white 
blotch posteriorly at base of laminated por- 
tion; issuing from elevated collars which are 
variegated with bright red and white and 
bordered with a narrow golden band. Bran- 
chial plumes six, golden with violet stems, 
retractile, and arranged in a circle around the 
low anal papilla, the two posterior pairs being 
closely united at their bases. Head small, 
usually concealed; from it a pair of oval, 
golden, leaf-like tentacles with intensely fold- 
ed borders extend laterally, their long axes 
directed laterally. Foot oblong and narrowed 
toward its truncate ends, extending beyond 
cloak posteriorly when animal is creeping, 
color beneath, yellow with golden border. A 
long dark blotch may appear at its center with 
the viscera showing through. Dorsally the 
foot is greenish yellow with lighter borders 
and with a white blotch on its median part 
near the posterior extremity. The ventral side 
of the body bordering on the foot is pinkish 
white; laterally the colors correspond to those 
of the dorsal surface. 
Length of holotype, when fully extended, 
76 millimeters, width 65 millimeters. 
Though smaller than many other specimens 
seen, this specimen was chosen for the holo- 
type as its coloration is typical of the species. 
It was found off the Hawaii Marine Labora- 
tory at Waikiki, within wading distance of 
the shore, February 2, 1922, by Robert Hope 
(U.S.N.M. 574927). 
Paratypes: 1 specimen, Mokuleia, Oahu, 
May 22, 1950; 1 specimen, found in reef pool 
1 foot deep, Hauula, Oahu, July 1, 1950, 
Mrs. Pauline Piltz; 2 specimens, near Elks 
Club, Waikiki, Oahu, April, 1923. 
In the many specimens that have come un- 
der my observation over a period of nearly 
30 years, I have found a close agreement in 
essential characters, such as would constitute 
a good species. While some variation in the 
intensity of coloring does occur, the only 
radical departure has been noted on the dorsal 
surface of the foot. This may vary from a 
grayish yellow with white markings, to a deep 
carmine. In all specimens observed, the gold- 
en margin of the cloak has been present, 
which seems a good descriptive character on 
which to base the name of the species. 
Most specimens have been found at Wai- 
kiki, where they may be seen swimming, or 
at rest on coral. Swimming is effected, as in 
H. tinkeri , by vigorous flexings of the body 
and undulations of the cloak margins. When 
the animal is at rest, the margins of the cloak 
are rolled up against its sides. 
A fluctuation in the size of the gills is 
found in some specimens, the middle pair 
being smaller than the others. The largest 
animal seen was found at Lanikai, Oahu, 
February 12. It measured 17 by 15 centimeters. 
The reproductive orifices, as in H. tinkeri , 
are located on the right side of the body, 
about one fourth the length from the anterior 
end, near the junction of the foot. The con- 
spicuous eversible penis is partly embraced 
on its posteromedial side by the semicircular 
female orifice. Copulation takes place as fol- 
lows: two individuals unite with heads turned 
