130 
PACIFIC SCIENCE, Vol IX, April, 1955 
Hope. It measures 13 by 10 centimeters (di- 
mensions of cloak when fully extended). Para- 
types bearing the following data are at hand: 
Nanakuli, Oahu, August, 1950, Charles Cut- 
ress; Pearl Harbor, Oahu, October 29, 1949 
(2 specimens), June 26, 1950 (1 specimen), 
July, 1950 (3 specimens, C. Cutress), Sep- 
tember 30, 1950 (1 specimen with margin of 
cloak dark red); on open shore of Oahu, 
November, 1949; Kailua, Oahu, March 19, 
1950; Kahala, Oahu, April 17, 1950. 
The largest specimen I have seen (the para- 
type from Kailua) was 23 centimeters long. 
I have named this conspicuous species for 
Mr. Spencer Tinker, Director of the Honolulu 
Aquarium, in appreciation of his very gen- 
erous aid in securing specimens of nudibranchs 
for me. 
The numerous specimens of H. tinker i ob- 
served from time to time, and obtained from 
various parts of Oahu, have shown little vari- 
ation. However, three specimens obtained 
from Pearl Harbor during 1950 had a marginal 
zone of the cloak, 3 centimeters wide, of a 
deep carmine, darkest near the margin. This 
zone corresponds to the three outer zones of 
the type (figured) and, in general, to all other 
specimens observed. This is probably only 
a color variation. The gills vary from six to 
eight in number. When there are six, which 
appears to be the usual number, they are 
arranged in a circle around the anal papilla, 
with three on each side. When seven gills 
are present, as in the type, one is placed in the 
median line between the anterior pair of the 
usual six. But when the animal has eight gills, 
the posterior gill on each side is represented 
by two smaller and closely approximated gills. 
An anomalous deviation from these typical 
arrangements has also been observed. 
Hexabranchus tinkeri is readily distinguished 
from H . aureomarginatus , another Hawaiian 
species, thus: 
Gills large and much branched, 6 or 7 in 
number; rhinophore sheaths with low, 
white collars; oral tentacles coarsely scal- 
loped. Color of animal yellowish or white, 
variegated with carmine or rose; margins 
of cloak carmine or pink . 
Hexabranchus tinkeri 
Gills rather small and less branched, 4 to 6 
in number; rhinophore sheaths with high 
collars variegated with white and reddish 
orange. Oral tentacles intensely scalloped. 
Color of animal bright orange red varie- 
gated with white; margins of cloak white 
with golden border 
Hexabranchus aureomarginatus 
It may also be compared with Hexabranchus 
sandwichensis (Souleyet and Eydoux), from 
which it differs in coloration and in mode of 
branching of the gills. Souleyet’s specimen 
was obtained from the Island of Hawaii, and 
it appears to be rare, since none answering to 
its description has come under my observa- 
tion during a period of about 30 years of 
research in this group. 
The description of H. sandwichensis is quoted 
from Souleyet and Eydoux (1852: 451, pi. 25, 
figs. 1-4). 
Doris sandwichensis, nobis. 
Cette grande et belle espece a le corps ovalaire, 
aplati, more, lisse; le dos d’un blanc bleuatre sur les 
cotes, et de couleur violacee sur la ligne mediane, est 
marque dans toute son etendue de taches pourprees de 
differentes grandeurs et irregulierement disposees; les 
bords du manteau tres-larges, minces et ondules, sont 
d’une belle couleur pourpre, interrompue en dessous 
par une bande blanchatre qui entoure le pied et qui 
se prolonge, en avant, an dela de la bouche et de ses 
appendices. Les tentacules superieurs, en form de mas- 
sue et lamelleux a leur sommet, sont egalement d’une 
couleur pourpre tre-Foncee. Les appendices buccaux 
sont large, a bords onduleux et comme franges. Le 
pied, de couleur Jaunatre, a a peine la moitie de la 
largeur du corps; ses bords sont minces et ondules 
comme ceux du manteau. Les branchies forment huit 
arbuscules disposes en cercle autour de 1’anus; cette 
ouverture est placee au centre d’un tubercule arrondi 
et saillant. 
Cette Doris habit les lies Sandwich; nous 1’avans 
recueillie a Hawaii, la principale des lies de ce groupe. 
Sa longueur est de douze a quatorze centimetres. 
Doris cardinalis Gould (1852: 302, pi. 25, 
figs. 397a-b) differs from H. tinkeri and H. 
aureomarginatus particularly in the oral tenta- 
