64 
PACIFIC SCIENCE, VoL XIII, January 1959 
from large adult specimens from deeper water 
in Lunada Bay and off Palos Verdes Point, 
14 mile to the north. The pellets were collected 
in small, screen-capped vials, and were kept 
in refrigeration until they could be examined 
and tabulated. 
Numerous specimens of Aplysia californka 
of various color combinations were kept from 
one to three months in 5 -gallon pyrex cylin- 
ders supplied with aeration and glass wool- 
charcoal filters. The sea water was changed as 
pollution made necessary. These animals were 
fed on special diets to determine associated 
color relationships. 
Hemolymph was drawn from the hemocoel 
after the animals had been cooled to refriger- 
ator temperature to render them inactive. 
This prevented the release of the contaminat- 
ing purple ink. The blood was centrifuged to 
remove the cellular elements, and the spectra 
were run on a Beckman model DU spectro- 
photometer. Extracts of the pigment of 
Plocamium pacificum were made by grinding 
the seaweed in a mortar with centrifuged sea 
hare hemolymph to duplicate the ionic con- 
ditions of the purple hemolymph occurring 
in certain specimens. 
Extractions of certain dermal pigments were 
made with weak hydrochloric acid. Usually 
10 per cent v/v was used, although one drop 
of concentrated hydrochloric acid in 10 cc. of 
distilled water would dissolve the pigment. 
The areas of the animal surface from which it 
was desired to extract pigment were cut off 
with scissors and placed in the dissolving 
solutions. These were then studied spectro- 
photometrically. 
EXPERIMENTAL DATA 
Fecal Pellets Analysis 
The diet of the young specimens of dark 
green and grey coloration consisted of a wide 
variety of algae, but the dominant representa- 
tives were Ceramtum eitoniannm and Gigartina 
canalicnlata. In no case was Plocamium paci- 
ficum present in noticeable quantity. All of 
the older specimens had red body streaks and 
a characteristic purple foot. In every case a 
varying but very noticeably dominant repre- 
sentation of Plocamium pacificum was found to 
be present. Other greener seaweeds were also 
present in small quantities. 
Controlled Feeding Experiments 
Specimens of Aplysia californka in all of the 
available color patterns were kept in the 
aquaria from one to three months and fed on 
a diet of parsley leaves and celery tops. These 
specimens all acquired a uniform pigmenta- 
tion characterized by a light-brown base color 
and small dark-brown spots. One large feed- 
ing of Plocamium pacificum fed to these speci- 
mens produced a decidedly pink cast to the 
base color. This, however, was only temporary. 
Two small red animals (2-3 inch) from the 
Plocamium beds north of Palos Verdes Point, 
apparently similar to the animals mentioned 
by Berry (1907), were kept in tanks in the 
laboratory. When captured, these young sea 
hares were a uniform light pink without 
markings, although one had a very few pin- 
point dots of brown. These animals thus bore 
no color resemblance to the greenish-brown 
or red-streaked Aplysia. It appeared at first 
that they constituted a new species, but after 
two weeks of feeding on parsley leaves they 
developed the coloration characteristic of A. 
californka. These two animals, fed on parsley 
leaves, grew to be 4 to 5 inches in length and 
so closely resembled other animals of similar 
size and experimental diet but of different 
initial coloration that it became impossible 
to differentiate them. 
Observations on the Pigments 
The blood, or hemolymph, of Aplysia is 
normally a clear fluid without noticeable 
coloration. However, it was found that speci- 
mens feeding principally on Plocamium pa- 
cificum possessed blood with a strong purple 
coloration. Spectro photometric curves were 
run on the blood and compared with extracts 
of Plocamium; however, while the curves them- 
selves proved interesting, they did not show 
common absorption maxima with those found 
