Food Habits of Aplysia — Winkler and Dawson 
105 
Zostera marina, during winter. Further studies 
are also needed on the diet of adult Aplysia 
calif ornica which, according to Limbaugh (per- 
sonal communication ) are most numerous at 
depths of 30-40 ft and have been observed 
as deep as 100 ft, depending upon concentra- 
tions of plants. He mentions them eating the 
"thinner red and green seaweeds.” 
From evidence now available it would appear 
that Aplysia calif ornica and A. vaccaria are not 
competitive for food, and that the former uses 
red and green algae as well as marine phanero- 
grams for food, while the diet of the latter is 
essentially restricted to the brown alga Egregia, 
at least in the tidal zone. The nutritive value of 
Egregia seems to favor growth to large size, for 
Limbaugh has reported observations of speci- 
mens of A. vaccaria in the subtidal zone measur- 
ing up to 30 inches and an estimated 35 lb, 
making them the giants of the gastropoda. 
SUMMARY 
Young Aplysia calif ornica on the open coast 
of southern California subsist on a diet mainly 
of fleshy red algae but show a preference for 
Ulva or Enteromorpha under artificial feeding. 
In the northern end of its range, where it ap- 
pears to become largely estuarine in habitat, all 
reports indicate that it feeds almost exclusively 
on green algae and eel grass, Zostera marina. It 
is suggested that the dietary differences may in- 
fluence its size as well as its color, and that an 
adquate winter food supply is an important 
factor. 
A. vaccaria appears to feed exclusively on the 
brown alga, Egregia. 
REFERENCES 
Eales, Nellie B. 1921. Aplysia. L. M. B. C. 
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MacGinitie, G. E. 1935. Ecological aspect of 
a California marine estuary. Amer. Midi. Nat. 
16: 737. 
1949. Natural history of marine ani- 
mals. McGraw-Hill, New York. 473 pp. 
Marcus, Ernst. 1961. Opisthobranch mollusks 
from California. Veliger 3 ( Suppl. ) : 9. 
Mazzarelli, G. 1893* Monographia delle Ap- 
lysiidae del Golfo di Napoli. Mem. Soc. Ital. 
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Winkler, Lindsay R. 1955. A new species of 
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1959^. A mechanism of color variation 
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66. 
1959 b. Intraspecific variation in the 
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