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PACIFIC SCIENCE, Vol. Ill, October, 1949 
Tonna perdix Linnaeus 
Description: Shell ovate, thin, large, hard; 
whorls about six in number; body whorl greatly 
inflated centrally, encircled by approximately 20 
very low, wide, contiguous, spiral ribs; spire 
not appreciably depressed, longer than in other 
species; aperture large, somewhat oblique; outer 
lip simple, thickened, without crenations; col- 
umella arched somewhat, but not twisted; color 
usually reddish-brown, marked by a reticulated 
pattern of white lines; inner margin of lips 
white; length, 2 to 6 inches. 
This species differs from all other members 
of the family in its longer spire and more 
oblique aperture. 
The color of this species is not uniform, nor 
is it enduring. Specimens are known which 
lack the usual color pattern and, instead, exhibit 
a nearly uniform coloration over the entire 
outer surface of the shell. The coloration does 
not seem to be permanent, for many specimens 
in collections seem to become progressively 
lighter with age. This fading appears to be 
increased by exposure to light. 
Ecology: This species is by far the most com- 
mon in Hawaiian waters, being apparently at 
least twice as abundant as all other species com- 
bined. It ranges in depth from less than 10 feet 
to well over 100 feet and is much more com- 
mon at the greater depths. 
Distribution: Circumtropical, including the 
Hawaiian Islands. 
Tonna melanostoma Jay 
Description: Shell ovate, large, thin, hard; 
whorls about seven in number; body whorl 
greatly inflated centrally, encircled by 18 to 20 
well-defined convex ribs with or without smaller 
intervening ridges; spire moderately well de- 
veloped, proportionately shorter than T. perdix ; 
aperture large, emarginate basally; outer lip 
simple, crenate, not thickened; columella ex- 
panded, reasonably straight, somewhat twisted, 
calloused; color of exterior white, yellow, brown, 
and black, darker in older specimens, grooves 
darker than intervening ridges; color pattern 
irregular but forming poorly defined longi- 
tudinal bands of brown, yellow, and white; 
outer lip marked by black; inner lip marked by 
black area which becomes large, dark, and 
shining in older specimens; length, 2 to 9 inches. 
Ecology: This species is second to T. perdix 
in abundance in Hawaiian waters. It does not 
seem to invade the shallower areas along the 
shore line as does T. perdix although specimens 
are not unknown in this area. 
This species, like all other shells of this 
family, is attacked by hermit crabs, including 
in particular Dardanus asper deHaan, the most 
common of the larger hermit crabs; Dardanus 
punctulatus (Olivier), a large red species meas- 
uring as much as 12 inches in length; and an- 
other large, white, unidentified species. 
Distribution: Indo-Pacific area including the 
Hawaiian Islands. 
Tonna dolium (Linnaeus) 
Description: Shell ovate, large, thin, hard; 
whorls about six in number; body whorl greatly 
swollen centrally, encircled by 12 to 16 well- 
defined spiral ribs which are separated by 
grooves of the same width with or without a 
smaller median spiral ridge in each groove; 
aperture large; outer lip simple, crenate, not 
thickened; spire normal, with sutures slightly 
depressed; columella reasonably straight, some- 
what twisted; color white or bluish-white, 
marked by quadrate brown spots upon the 
ridges, these spots being separated by a distance 
equal to their width; color of grooves darker 
than intervening ridges; length, 3 to 5 inches. 
Ecology: This species is fourth among the tun 
shells in abundance in Hawaiian waters. It is 
a rare form and is known only from those speci- 
mens mentioned below, all from the same local- 
ity. These specimens were procured by Fer- 
nando Leonida, a fisherman who operates a set 
of wire fish traps along the southwest shore of 
Oahu, and were taken from these wire traps 
at the outer edge of the reef platform at depths 
of approximately 15 fathoms. At the time of 
their capture, all of the specimens were occu- 
pied by various species of hermit crabs, a fact 
which accounts for the presence of the shells 
