The Little Hearts (Corculum) of the Pacific and 
Indian Oceans 
Paul Bartsch 1 
Form, coloration, and rarity place the 
Little Hearts among the most attractive bi¬ 
valve mollusks of the Pacific and Indian 
Oceans. They have been prized objects of 
collectors since the early days of molluscan 
history. 
It was a pleasing surprise to receive for 
determination recently, from Dr. Asela 
Franco, 25 specimens of Little Hearts 
with copious notes on others in her col¬ 
lection. The surprise was justified, for 
during the cruise of the U. S. Bureau of Fish¬ 
eries Steamer "Albatross,” covering most of 
the Philippine Archipelago, I took only two 
specimens, on a reef at Tilig, Lubang Island. 
Dr. Franco says: "Across from Cebu City 
separated only by a small channel is the small 
island of Mactan, where Magellan was 
killed. East and south of Mactan are several 
still much smaller islands. During low tide 
one can walk from one to another of these 
islands in some places. The heart shells are 
found west, south, and east of Mactan, or in 
the waters between Cebu City and Mactan 
and between Mactan and the neighboring 
small islands on the south and east sides. 
Not only heart shells are found in these 
places, but most of my shells were collected 
there. It is my favorite collecting locality, 
as it is near the city. All these smaller 
islands mentioned belong to Cebu. 
"Heart shells are collected during low 
tide, not beyond about two feet of water. 
They are usually found among fine broken 
corals or in sandy places, the dorsal side 
1 Associate, Division of Mollusks, United States 
National Museum. Manuscript received February 
26, 1947. 
being buried a few centimeters deep. Some¬ 
times they are found flat down on the pos¬ 
terior side, perhaps because of the current 
during high or low tide. Rarely one could 
see them among seaweeds, and they are 
never attached to any corals or stones. They 
are not found in groups or bunches, and 
both colored and white ones or different 
types may be seen in the same region. More 
heart shells are collected during the months 
of May and June.” 
Dr. Franco’s sending is particularly rich 
in color markings, a fact which is helpful in 
interpreting what some of the names be¬ 
stowed by the early writers embraced. Most 
of the early specific names were based upon 
coloration. That coloration was not a con¬ 
stant but a variable feature was then un¬ 
known, and this fact was responsible for the 
list of synonyms here noted. 
Dr. Franco’s collection, combined with the 
42 lots in the National Museum from vari¬ 
ous localities, enables me to revise the genus 
and bring the nomenclature up to date. 
Corculum Roding 
1798. Corculum Roding, Mus. Bolt., p. 188. 
1811. Cardissa Megerle von Muhlfeldt, Mag. Ges. 
Naturf. Fr. Berlin 5ter Jahrg., p. 52. 
1870. Type designation by von Martens Cardium 
cardissa L. Zool. Rec. for 1869, p. 586. 
Little Hearts are members of the family 
Cardiidae. They have a thin shell which is 
anteriorly-posteriorly compressed, the two 
valves of which when viewed anteriorly or 
posteriorly present a heart-shaped outline. 
The lateral edge of the shell, i.e., the middle 
of the valves, curves forward or back de- 
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