302 
PACIFIC SCIENCE, Yol. XI, July, 1957 
of 4 to 10 feet in the lagoon west of Saipan. 
GEOGRAPHIC range: Apparently limited to 
the Pacific. USNM collections are from the 
Philippine, Mariana, Caroline, Marshall, Sa- 
moan, Cook, Society, Line (Palmyra), and 
Hawaiian islands. 
Cypraea ( Mauritia ) mauritiana Linne, 1758. 
Tinker (1952) p. 140, 3 figs, on p. 141; 
Morris (1952) p. 179, pi. 5, fig. 13; Kira 
(1955) pi. 20, fig. 12. 
A large species, characteristically 3.5 to 4 
inches long with brown dorsal reticulations 
and blackish-brown angular margins. 
Ordinarily found under rocks or in rock 
crevices on windward ocean reef flats, com- 
monly just shoreward of the reef edge where 
the surf is strong. Also taken from the fronts 
of both windward and leeward reefs, the walls 
of surge channels in the reef edge, in shallow 
water on small lagoon reefs, on lagoon reef 
flats, and along rocky shores. Characteristic- 
ally lives below low tide line, but also occurs 
intertidally in moist rock crevices and tide 
pools. Ingram (1947) collected immature 
specimens from a pool on a ledge of lava near 
Hanauma Bay, Oahu. The pool was about 15 
feet above the breaking surf at high tide and 
was sprayed by waves only during high water. 
Ingram also observed that individuals of the 
same size ordinarily live together under simi- 
lar environmental conditions. This species is 
nocturnal. 
geographic range: USNM collections are 
from Cocos-Keeling Atoll in the Indian 
Ocean eastward through the Pacific to the 
Society, Tuamotu, and Hawaiian islands, and 
from southern Japan south to New Guinea 
and New Caledonia. Allan (1950) reports C. 
mauritiana to be "fairly common" on the 
Great Barrier Reef of Australia. It is common 
in Micronesia. 
Subgenus Erosaria Troschel, 1863 
Cypraea ( Erosaria ) caputserpentis Linne, 1758. 
Tinker (1952) p. 156, 3 figs, on p. 157; 
Morris (1952) p. 179, pi. 5, fig. 2; Kira 
(1955) pi. 19, fig. 24. 
Characteristically 1.25 to 1.5 inches long 
with brown reticulations over a white dorsum, 
angular brown margins with white or grayish 
extremities, and white teeth with brown inter- 
stices. 
In Micronesia, C. caputserpentis is apparently 
most abundant among rocks on windward 
ocean reef flats, just shoreward of the reef 
edge. It is also found on the walls of surge 
channels along the seaward reef edge, on 
leeward ocean reefs, on lagoon reef flats, and 
on small lagoon reefs. It ordinarily lives in 
shallow water below low tide line but also 
occurs intertidally in moist rock crevices and 
in tide pools. Ostergaard (1950) reports that 
in Hawaii, large numbers of this species com- 
monly occur together on shore rocks washed 
by the surf at high tide. 
GEOGRAPHIC RANGE: USNM collections are 
from East Africa eastward through the Indian 
and Pacific oceans to the Society, Tuamotu, 
and Marquesas islands, and from southern 
Japan, the Hawaiian and Line islands south 
to northern Australia and New Caledonia. A 
very common species throughout the Indo- 
Pacific. A form or subspecies of C. caputser- 
pentis is found at Easter Island in the eastern 
Pacific. 
Cypraea ( Erosaria ) erosa Linne, 1758. 
Tinker (1952) p. 148, 3 figs, on p. 149; 
Kira (1955) pi. 19, fig. 25. 
Characteristically about 1.5 to 2 inches 
long, with thickened, pitted margins and ex- 
tremities which are white with brown ridges. 
Each margin is medially marked with a large,, 
squarish, purple-brown splotch. 
Lives among rocks and coral heads just 
below low tide line on the outer parts of both 
seaward and lagoon reefs. Abbott (1950) re- 
ports three living specimens from pools on 
the outer reef of Cocos-Keeling Atoll. 
geographic range: USNM collections are 
from East Africa eastward through the Indian 
and Pacific oceans to the Society and Tua- 
